Not to talk about N97, N97 mini that pioneered the mechanism and while those phones have had their share of problems never have i heard bad things about the tilt slider. If the thinner looking E7 can make it work why not the RM680.
And btw wasn't that whole news started by Eldar, Nokia is more than strickt about talking devices not yet announced. My guess is that rm680 simply got sidelined as getting the soft out took so long and they moved to next wave of protos.