Wilkinson also makes a bass wiggle-stick. Don't know about a bass locking- or roller nut, but I'd definitely want Sperzel locking bass keys. A lot of times it goes out of tune as you lose tension on the wraps around the tuning posts, and the Sperzels would eliminate that. The locking nuts eliminated that, but geez I remember every guitar player I ever worked with just cussing those things. Later on, Fender went to using a roller nut (the LSR)to eliminate any binding in the nut slots, with locking keys to try to get around that. Think of a metal nut with a wheel in the bottom of each slot and you get the idea. As you pulled the stick back and forth, the strings would roll slightly in their slots, and since the strings were pinned in the locking key posts, it was an alternative to the Floyd layout.
I don't remember if the Sperzels are a direct replacement, seem to think they need a slightly different-sized hole. Maybe someone else has experience with them, very simple to use.
J o e y