The sleds I used were cut from sheets of plexiglas to fit snugly in the rails. I drilled 4 holes through the bottom to support a 3.5" ff drive. Tempered Masonite hardboard could also be used, and then you wouldn't have to have static buildup precautions. Metal sheets with retention brackets would be nicer, but I was going for quick and cheap (materials on-hand) With 1" drives, you can mount 2 in each BA4x0 drive bay, one per "sled" per guide. As before, I don't know how much power can be safely taken of of one drive sled connector, but I have the TK70, HSD05 and one 1/3 ht Seagate Barracuda 4GB drive working off of one sled with no trouble (haven't actually used the TK70 yet, no tapes, but it's plugged in and everything seems cool).