I'm fond of 22 guage wire. Silent, easily stored in a PSK and you save all that energy.

My hesitation to try the .17 rimfires stems from thier very velocity.

Review of physics:
Force = Mass * |Acceleration|

Now, with a smaller bullet, you have to have greater velocity (acceleration occures as it slows in the target, even if it is a negative number). Higher velocity rounds usually do more meat damage; with smaller animals, that's kinda the crititcal factor. How much more or less meat loss is there in similiar sized animals of the same (family of) species have you seen with the .17 than you have with the regular .22s. And yes, I'll keep in mind the initial velocity differences with your answers.

If there isn't much difference, then I might have to think about it for next purchase.

That being said, I like Chris's suggestion. You can get a lot of .22 ammo for the weight of 50 rounds of centerfire pistol ammo, or a bit over a hundred feet of wire for the same mass and bulk.