IIRC, you can't UMD Insightful Damage scrolls; or rather you can, but it only applies to your mainhand and since that's where you have to equip the scroll, it's useless to do so.

So without Harper, there's no other way of getting INT to damage with 1H melee weapons on a pure rogue. Fortunately, you'd still have high base DEX anyway for your ranged feats, if nothing else, so DEX to damage from Assassin cores is a reasonable backup.
Also the silver lining to no Harper is you can afford the 41 Assassin / 31 Mechanic / 3 Acrobat AP split I mention in my thread.
That said, you would be better off sticking with a regular pure Mechanic (or Assassin) on a halfling rogue, IMO. The Mechassin was always a flavor build, but losing the human bonus feat makes it even tougher to pull off.
Having said that, if you still want to give it a go - well, I respect the crazy, so here's what I would do.
Code:
Half-pint Mechassin
Rogue 20
True Neutral Halfling
Stats
28pt 32pt Level Up
---- ---- --------
Strength 8 8 4: DEX
Dexterity 18 18 8: DEX
Constitution 14 16 12: DEX
Intelligence 16 16 16: DEX
Wisdom 8 8 20: DEX
Charisma 8 8 24: DEX
28: DEX
Skills
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
------------------------------------------------------------
Disable 4 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 23
Open Lo 4 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 23
Search 4 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 23
Spot 4 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 23
Bluff 4 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 23
Hide 4 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 23
Move Si 4 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 23
Tumble 4 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 23
Haggle 3 2 2 2 2 2 2 2 2 2 2 23
UMD 4 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 23
Concent 2 1 1 1 1 1 1 1 1 1 11
Balance 1 1
------------------------------------------------------------
44 11 11 11 11 11 11 11 11 11 11 11 11 11 11 11 11 11 11 11
Feats
1 : Rapid Reload
3 : Precision
6 : Two Weapon Fighting
9 : Improved Two Weapon Fighting
12 : Improved Critical: Piercing
15 : Greater Two Weapon Fighting
18 : Point Blank Shot
21 Epic : Improved Sneak Attack
24 Epic : Overwhelming Critical
26 Destiny: Perfect Two Weapon Fighting
27 Epic : Blinding Speed OR Epic Damage Reduction
28 Destiny: Doubleshot
29 Destiny: Harbinger of Chaos OR Deific Warding
30 Epic : Combat Archery OR Epic Damage Reduction
30 Legend : Scion of: Ethereal Plane
10 Rogue : Opportunist
13 Rogue : Improved Evasion
16 Rogue : Crippling Strike
19 Rogue : Defensive Roll
Enhancements (80 AP)
Assassin (43 AP)
- Knife in the Darkness, Dagger in the Back, Assassin's Trick, Nimbleness, Lethality, Deadly Shadow
- Sneak Attack Training, Stealthy III
- Poison Strikes: Heartseeker, Venomed Blades III, Sneak Attack Training, Damage Boost III
- Sneak Attack Training
- Execute, Killer III, Weakening Strikes, Sneak Attack Training
- Assassinate, Measure the Foe III, Deadly Strikes, Knife Specialization, Light Armor Mastery III
Mechanic (31 AP)
- Arbalester, Tanglefoot, Targeting Sights, Improved Detection, Expert Builder
- Sharpshooter, Thunderstone III
- Sharpshooter, Improved Traps III
- Sharpshooter, Ooze Flask III, Intelligence
- Sharpshooter, Fletching III, Leg Shot, Intelligence
Halfling (3 AP)
Thief-Acrobat (3 AP)
- Staff Control
- Fast Movement
Leveling Guide
- Mec0 Arbalester; Mec1 Sharpshooter; Mec1 Thunderstone I
- Mec1 Thunderstone II, III; Mec2 Sharpshooter
- Mec0 Tanglefoot; Mec2 Improved Traps I; Mec3 Sharpshooter
- Mec2 Improved Traps II, III; Mec3 Intelligence
- TA0 Staff Control; TA1 Fast Movement; Mec3 Ooze Flask I
- Mec0 Targeting Sights; Mec3 Ooze Flask II, III; Mec4 Fletching I
- Mec4 Fletching II, III; Mec4 Sharpshooter
- Mec4 Leg Shot; Mec4 Intelligence
- Ass0 Knife in the Darkness; Ass1 Sneak Attack Training; Ass1 Stealthy I
- Ass1 Stealthy II; Ass0 Dagger in the Back; Ass2 Sneak Attack Training
- Ass1 Stealthy III; Ass2 Damage Boost I, II, III
- Reset Mechanic
- Assassin: Assassin's Trick, Nimbleness
- (none)
- Poison Strikes: Heartseeker, Venomed Blades III
- Sneak Attack Training
- Execute, Killer III, Weakening Strikes, Sneak Attack Training
- Assassinate, Measure the Foe I, Knife Specialization
- Mechanic: Arbalester, Tanglefoot, Targeting Sights
- Sharpshooter, Thunderstone III
- Improved Traps III
- Ass5 Measure the Foe II, III; Ass5 Deadly Strikes
- Mec2 Sharpshooter; Mec3 Sharpshooter
- Mec3 Intelligence; Mec3 Ooze Flask I, II
- Mec3 Ooze Flask III; Mec0 Improved Detection; Mec4 Sharpshooter
- Mec4 Intelligence; Mec4 Leg Shot
- Ass0 Lethality; Mec4 Fletching I, II, III
- Mec0 Expert Builder; Ass5 Light Armor Mastery I, II, III
- Ass0 Deadly Shadow; Hlf0 Halfling Luck; Hlf0 Dexterity
Rather than INT-primary DEX-secondary, I reversed the key stats, since (A) I still see this as primarily a melee build in the long run, so without Harper I focus on DEX to damage for melee and (B) it's more F2P/newbie-friendly since you don't need any tomes this way.
Although as with the original Mechassin, I recommend focusing on great xbows for early leveling. Naturally if you wish to melee first, you need to tweak Enhancements and possibly feat order (take TWF sooner). In the long run, I'd use a keen repeater, such as
Fatal Flaw or the new
Stormreach Guardian. These become 17-20/x3 with Expert Builder.