I have been playing a lot Diablo 3 and loving the demon hunter idea, dual wielding hand crossbow. I was trying to come up with a character concept. The reloading hand crossbow takes a move action, but with the feat Rapid Reload it is turned to a free action. I this works with both the crossbow or if it only applies to only one. If this feat doesn't do this it will cause this concept fall apart. Can anyone help me out on this idea.
well its a tricky one
yes the feat would let you reload both as a free action however its says in the hand crossbow entry that you can shoot, but not load, a hand crossbow with one hand at no penalty.
If your using two hand crossbows then technically you'd need a 3rd hand that would be free to help reload each as a free action.
If you come up with a really cool concept your GM may just let it fly.
If you really want to have this work RAW then you'd need to took at getting something like the vestigial arm discovery from the alchemist to provide you with an extra arm that could help reload. It would only require a 2 level dip into alchemist to get the discovery, plus that also opens you up to taking more feats with the extra discovery and there are alot of good discoveries which can enhance other classes.
On a side note have a look at the Master Chymist prestige class for alchemists gives brutal bonus damage to using simple weapons, a light crossbow is a simple weapon
you could techincally have 2 vestigal arms and shoot and reload 2 light crossbows with your 4 arms and get a nice damage bump on the attacks