hi

for a 29 with goldies i'd probably go with some kind of shrimp, most other bottom feeders i can think of are tropical (otos, kuhlis, cories) that sort of thing, the only other coldwater bottom feeders that i know of are dojo or weather loaches, but they get too big for your 29 and need to be in groups.
a 10 gallon is probably too small for a BN pleco considering that it has such a small footprint, but you might be able to get a clown pleco (they stay a little smaller)