I have seen a discussion on this stating it still takes 2 hands to reload which makes no sense to me really. Let me go over the mechanics of why this make no sense.
The 'mechanics' you go over simply deal with cost and damage as compared to the light crossbow, not actually thinking critically over what true mechanics are required to fire a hand crossbow. Granted, this is a fantasy game where certain liberties are taken with certain actions, but I personally have shot a hand crossbow, and physically it would be highly unlikely, if not impossible, to dual wield these things and expect to reload them as a free action.
And now, to mechanics: a hand crossbow in real life has different weights attributed to it's draw (similarly represented by +Str bows in Pathfinder). I am currently looking at one particular pistol crossbow with an 80 lb. draw. Having also practiced heavily with a compound bow in my mid-teens, an 80 lb. draw isn't something to laugh at (YMMV depending on aptitude, however). Now, a compound bow utilizes both hands and arms to draw that kind of weight, whereas you're only pulling a hand crossbow back 8-10" until it locks. I really want you to try this while holding anything in your other hand and then loading the bolt in place. Granted you have resistance from the other hand holding the grip, but you honestly can't expect to get this done in a timely or even safe manner. Pulling the string back with one or two fingers while still holding the other weapon is going to be tough, not to mention the fact that you still need to do it with the other hand, coupled with the fact that you still need to actually set the bolts in place afterwards make for a fairly unrealistic (yes, I know it's a fantasy game) action, especially when you want it as a Free Action.
Yes, you're taking multiple feats to gain proficiency and the aptitude to reload faster. No, you can't dual wield them. Keep that insanity for your computer. On a similar, if unrelated subject, a character can't 'switch grips' for melee weapons (i.e. going from one-handed to two-handed or vice versa) during their attacks, and I personally find that much easier to digest than the flavor of the D3 Demon Hunter. Although if you were to somehow invent a repeating hand crossbow modeled after the Repeating Heavy and Light Crossbows found in the Core Rulebook, where the lever you needed to engage utilized, say, a bump against your hip action, I could see this being plausible. The price would obviously be higher than the 100g hand crossbow (judging by the math used between the normal light and heavy crossbows to the repeating ones, I'd say you're still looking at between 7 and 8 times the price, for a grand total of 700-800g for a repeating hand crossbow).
If you're simply concerned with the 'bang for your buck' issue, the hand crossbow isn't an everyday item. It's exotic for a reason. Originally presented as a drow weapon, this little guy is one quick hand gesture away from an assassination attempt. Try skulking around with a light or heavy crossbow hidden under your cloak as you're going from parapet to parapet trying to get that one clean shot at the tyrannical warlord or the king you've been hired to assassinate. It doesn't bring the flavor of subterfuge and stealth that the hand crossbow does. Sure, it doesn't shoot as far. It's a handgun compared to a high-powered rifle. It doesn't do as much damage. That's what poisons are for. It's high priced compared to its more common cousins. You won't see a town's guard with a hand crossbow at his belt. His job is to drop enemies that are sometimes beyond that 30' range increment. Perhaps in some societies (i.e. drow), the hand crossbow is more common and could be purchased at a lower price.
If you're talking flavor by trying to convert a point and click shooter class with a game as well-developed as Pathfinder, I'd be ready for some disappointment due to the RAW. You could theoretically take enough Craft (Engineering) skill ranks to begin plans for a Repeating Hand Crossbow, but that's going to go way over your qualms about price per point of damage equation you've mentioned above.
When I played D3, you're damn right I played a Demon Hunter. Fun class, fun story, loved the look. Play an Inquisitor or Gunslinger here or a Paladin with a lot of ranged feats, or even a Fighter with a cool backstory. But if it's just a matter of finding a DM that would allow you to bend/break the rules, it's probably better off left alone.
Good luck to you if you come up with something plausible outside of the cost>damage analogy. That particular weapon is not designed for what you're looking for as is, but I'd love to see some legitimate attempts at making a repeating hand crossbow. Just remember, the damage is still going to be low and you're still going to pay an arm and a leg for it.