I was not sure from reading the forums, so I tried my Turbo Color slab having a 3.1 v71 ROM with an ADB soundbox and was able to use a standard ADB keyboard and mouse. Yey! With my KVM switch, that's one less set of keyboard/mouse/monitor on my desk!
Forum entries sort of indicated a v74 ROM was needed. Andreas alluded in
http://www.nextcomputers.org/forums/viewtopic.php?t=428 that v71 can be used, and I confirm that.
That's cool. :) I remember reading posts on Usenet that some of the earlier ROMs had features of the v74 code. IIRC, it was posted by NeXT hardware guru Mike Paquette.