Well, if you believe the Wikipedia entry, a bitterant can leave a residue. I suppose to figure out any potential damage you'd need to know the identity of the bitterant(s) in question so as to look up the chemical properties. Unfortunately, none of the cans I have on hand (various brands) identify any of the contents.
You'd hope that the selection process would involve criteria minimizing side effects and leaving the product still suitable for its intended purpose. It's only anecdotal evidence, but I've used the stuff for years and never noticed any damage.
I have one can that doesn't seem to contain a bitterant (not mentioned on the can, anyway), but it could easily be 10 years old. It's a Dust-Off DPSXL, the rest that contain the bitterant notices are DPSX12 (the ones that are Dust-Off/Falcon anyway). I don't know if the DPSXL model is still available commercially, but it might be. The MSDS only lists Diflouorethane.
According to a suggestion in this MetaFilter question, you might try looking for products intended for photo use. Maybe a camera store or photo supply outfit? Maybe they still carry the DPSXL as the lab supply outfit I linked to above appears to?
I've got a duster than consists of a valve/trigger assembly that takes CO2 cartridges. I think this is it. Looks like Newegg doesn't carry it any more, but you can find similar products on Amazon. This is probably the way to go if you want to avoid bitterant agents and can't get your hands on any suitable cans of Diflouorethane.