hrm, i dunno about peripherals. I have had some of those neoprene-gel wrist rests for teh keyboard and the mousepad, and they felt way too much like a coed in a wetsuit... I think anything more realistically skinned would be a distraction. Besides, if a 'peripheral' was larger than a handful, it would be a waste, right?
( On a side note, somehow the supposedly ergonomic headrests i had were actually cutting off circulation when I rested my wrists on them. No one realized, i guess, that there are some major blood vessels running through your wrist... reaaaaaaally well though out, those things.

)