Having done "The Melee Thing" for a while, and not caring too much for hurling spells, I was contemplating a few different ideas around Repeating Crossbows. There's something fun about using a wanna-be machine gun. While Melee is the obvious DPS Supremacy Front, Ranged does has it's advantages as well.
As for the Classes to pull this off, I know Bard is a seemingly 'popular' Repeater choice. Everybody likes a walking buff-bot with a machine gun, right?
A few thoughts of my own, be they presented before or not, were involving either going Fighter (And Kensai) and focus purely on Repeaters. With all the bonus feats, it doesn't seem impossible to get everything needed to make the Crossbow do respectable damage. (That, and Piercing multiple monsters with a Repeater puts a grin on my face.) Added with the Fighter traits of Good HP and Heavy Armor, "Squishy" isn't a word I'd use.
Secondly, there's the obvious choice of Ranger. While Tempest might be the standby, Arcane Archer seems to be an interesting choice. While I know Arcane Archer can only conjure Arrows, would Force Arrows effect Bolts? Regardless, the Archer feats to Ranged are worth considering, as well as other attributes to assist in this build. I think there is a Repeater Ranger build somewhere, and possibly a comparison to Fighter. Would have to double check, but I'm 90% sure the comparison has been made before.
Finally, there's Rogue. With having the natural affinity to Dex as a Ranger does, I was curious if Sneak Attack applies to all the shots fired by a Repeater? With Rogues being a popular party choice as it is, the thought of seeing a sudden surge of numbers explode with Base Damage, Elemental Damage, and Sneak Attack damage kind of makes me grin like an idiot. The only problem I see with Rogue is the lack of Feats to help with the Ranged Shenanigans as early as Fighter or Ranger.
Of course, the last thing to consider is Race. While Drow and Elf have their Dexterity Bonuses (Racial and Enhancement), Halfling has things to bring to the table as well, and Human has their standby of Bonus Feats and Skills.
I suppose Multiclassing is an option as well, since I'm not sure how many "Capstone" abilities would benefit this path, but eh, why play the game if it's not to have fun? Multiclassing suggestions are viable as well.
So, ultimately, Bard vs. Fighter vs. Ranger vs. Rogue, and Elf/Drow vs. Human vs. Halfling. I don't need a build laid out for me, just suggestions and comments.