zardoz has done some excellent work in this scene but he's been very quiet over the past year or so - I am not expecting to see an update of his emulator anytime soon.
supposedly he helped rlyeh with speeding up his 68k core for the fGen/fMame emu's, I expect we'll see those surface eventually.
also, in light of yoyo's new project, maybe he (+ his group) will pick up the torch next - who knows! It's hard to say - the group of emu developers in this scene, although prolific (damned prolific!) is still pretty small so that means we have to wait a bit of a while in between high-profile releases, such as a Genesis emulator.
Zardoz, Skeezix, Black - are any of them still officially involved (developing) in this scene, I wonder? (I don't watch the dev. forums so I am not too up-to-date I guess)