I put together another random build. I'm honestly not sure if the bonuses from Battle Engineer and Kensai stack with each other, but if they do, this honestly seems like it would be better than a pure Artificer, or a pure Fighter, when using a Repeating Heavy Crossbow. The only bad thing is that neither class has a +DEX Enhancement line.

I'm also not sure, but Crossbows still use DEX as their damage modifier, right? The wiki seems to have "n/a" on all of the Crossbows for Damage, but they still say DEX for to-hit.

Code:
Character Plan by DDO Character Planner Version 03.12.02
DDO Character Planner Home Page

Level 20 Lawful Good Human Male
(14 Fighter \ 6 Artificer) 
Hit Points: 348
Spell Points: 315 
BAB: 18\18\23\28\28
Fortitude: 15
Reflex: 14
Will: 9

                  Starting            Ending          Feat/Enhancement
Abilities        Base Stats         Base Stats         Modified Stats
(28 Point)       (Level 1)          (Level 20)           (Level 20)
Strength              8                 10                   14
Dexterity            18                 25                   26
Constitution         16                 18                   18
Intelligence         10                 12                   12
Wisdom                8                 10                   10
Charisma              8                 10                   10

Tomes Used
+2 Tome of Strength used at level 7
+2 Tome of Dexterity used at level 7
+2 Tome of Constitution used at level 7
+2 Tome of Intelligence used at level 7
+2 Tome of Wisdom used at level 7
+2 Tome of Charisma used at level 7

                  Starting            Ending          Feat/Enhancement
                 Base Skills        Base Skills        Modified Skills
Skills           (Level 1)          (Level 20)          (Level 20)
Balance               4                 19                   19
Bluff                -1                  0                    2
Concentration         7                 13                   15
Diplomacy            -1                  0                    2
Disable Device        n/a               n/a                   n/a
Haggle                3                  9                    9
Heal                 -1                  0                    0
Hide                  4                  8                    8
Intimidate           -1                  0                    2
Jump                 -1                 25                   25
Listen               -1                  0                    0
Move Silently         4                  8                    8
Open Lock             8                 17                   17
Perform              n/a                n/a                   n/a
Repair                0                  1                    1
Search                0                  1                    1
Spot                  3                 16                   16
Swim                 -1                  3                    3
Tumble                6                 10                   10
Use Magic Device     n/a                n/a                   n/a

Level 1 (Artificer)
Skill: Concentration (+4)
Skill: Haggle (+4)
Skill: Open Lock (+4)
Skill: Spot (+4)
Skill: Tumble (+2)
Feat: (Human Bonus) Extend Spell
Feat: (Selected) Toughness
Spell (1): Conjure Bolts
Spell (1): Enchant Armor
Enhancement: Artificer Damage Boost I
Enhancement: Artificer Crossbow Damage I
Enhancement: Human Versatility I


Level 2 (Artificer)
Skill: Balance (+0.5)
Skill: Concentration (+1)
Skill: Haggle (+1)
Skill: Open Lock (+1)
Skill: Spot (+1)
Spell (1): Shield of Faith
Enhancement: Human Improved Recovery I
Enhancement: Artificer Energy of Creation I


Level 3 (Artificer)
Skill: Balance (+0.5)
Skill: Concentration (+1)
Skill: Haggle (+1)
Skill: Open Lock (+1)
Skill: Spot (+1)
Feat: (Selected) Weapon Focus: Ranged Weapons
Spell (2): Cat's Grace
Enhancement: Uncaring Master
Enhancement: Racial Toughness I


Level 4 (Artificer)
Ability Raise: DEX
Skill: Balance (+0.5)
Skill: Concentration (+1)
Skill: Haggle (+1)
Skill: Open Lock (+1)
Skill: Spot (+1)
Feat: (Artificer Bonus) Point Blank Shot
Spell (2): Elemental Weapons
Enhancement: Artificer Damage Boost II
Enhancement: Artificer Crossbow Attack I
Enhancement: Human Versatility II


Level 5 (Artificer)
Skill: Balance (+0.5)
Skill: Concentration (+1)
Skill: Haggle (+1)
Skill: Open Lock (+1)
Skill: Spot (+1)
Spell (2): Bear's Endurance
Enhancement: Human Adaptability Dexterity I
Enhancement: Artificer Energy of Creation II


Level 6 (Artificer)
Skill: Balance (+0.5)
Skill: Concentration (+1)
Skill: Haggle (+1)
Skill: Open Lock (+1)
Skill: Spot (+1)
Feat: (Selected) Rapid Shot
Spell (3): Flame Turret
Enhancement: Artificer Battle Engineer I


Level 7 (Fighter)
Skill: Balance (+0.5)
Skill: Jump (+2)
Feat: (Fighter Bonus) Precise Shot
Enhancement: Fighter Attack Boost I
Enhancement: Fighter Critical Accuracy I
Enhancement: Racial Toughness II


Level 8 (Fighter)
Ability Raise: DEX
Skill: Balance (+1)
Skill: Jump (+2)
Feat: (Fighter Bonus) Power Critical
Enhancement: Human Versatility III
Enhancement: Fighter Toughness I


Level 9 (Fighter)
Skill: Balance (+1)
Skill: Jump (+2)
Feat: (Selected) Dodge
Enhancement: Fighter Flanking Mastery I


Level 10 (Fighter)
Skill: Balance (+1)
Skill: Jump (+2)
Feat: (Fighter Bonus) Weapon Specialization: Ranged Weapons
Enhancement: Fighter Attack Boost II
Enhancement: Fighter Critical Accuracy II
Enhancement: Fighter Toughness II


Level 11 (Fighter)
Skill: Balance (+1)
Skill: Jump (+2)
Enhancement: Human Improved Recovery II


Level 12 (Fighter)
Ability Raise: DEX
Skill: Balance (+0.5)
Skill: Jump (+3)
Feat: (Selected) Improved Critical: Ranged Weapons
Feat: (Fighter Bonus) Mobility
Enhancement: Fighter Kensei I


Level 13 (Fighter)
Skill: Balance (+0.5)
Skill: Jump (+3)
Enhancement: Kensei Repeating Heavy Crossbow Mastery I
Enhancement: Fighter Strength I


Level 14 (Fighter)
Skill: Balance (+0.5)
Skill: Jump (+1)
Skill: Spot (+1)
Feat: (Fighter Bonus) Greater Weapon Focus: Ranged Weapons
Enhancement: Human Greater Adaptability Strength I


Level 15 (Fighter)
Skill: Balance (+0.5)
Skill: Jump (+1)
Skill: Spot (+1)
Feat: (Selected) Improved Precise Shot
Enhancement: Fighter Critical Accuracy III


Level 16 (Fighter)
Ability Raise: DEX
Skill: Balance (+0.5)
Skill: Jump (+1)
Skill: Spot (+1)
Feat: (Fighter Bonus) Shot on the Run
Enhancement: Fighter Strength II


Level 17 (Fighter)
Skill: Balance (+0.5)
Skill: Jump (+1)
Skill: Spot (+1)
Enhancement: Fighter Strength III


Level 18 (Fighter)
Skill: Balance (+0.5)
Skill: Jump (+1)
Skill: Spot (+1)
Feat: (Fighter Bonus) Greater Weapon Specialization: Ranged Weapons
Feat: (Selected) Precision
Enhancement: Kensei Repeating Heavy Crossbow Mastery II
Enhancement: Fighter Kensei II
Enhancement: Fighter Repeating Heavy Crossbow Specialization I


Level 19 (Fighter)
Skill: Balance (+0.5)
Skill: Jump (+1)
Skill: Spot (+1)
Enhancement: Fighter Flanking Mastery II


Level 20 (Fighter)
Ability Raise: DEX
Skill: Jump (+1)
Skill: Spot (+1)
Skill: Swim (+1)
Feat: (Fighter Bonus) Sap
Enhancement: Fighter Critical Accuracy IV