As Vlk said many times, avast! 5.0 won't be released any time soon, most probably not before Windows Vista release and even then it's not sure if they'll really release it.
I belive they'll have to start saying like ESET and 3DRealms guys: "It's done when it's done!" They'll probably release beta first and we might even get some "insider" info from Alwil team even before that. Who knows, they'll surprise us for sure.