Not that many, actually. Of the big mods, only Thaumcraft, Railcraft, EE3, and Xycraft don't have at least Alpha builds out, and all those have posted something within the past week of ongoing progress. Of the smaller mods, Xeno's Reliquary and Extra Bees seem to be the biggest hold outs there. I think the Direwolf pack has just about 10 mods I can't point out progress on fairly trivially, and a lot of those are add ons to a mod that hasn't left Alpha/Beta yet.I kind of suggested that before. I think it's a totally viable solution. And not just for RP2, but any of the mods that lagged behind after a certain time period. There are still 20 something mods that we don't know the status of yet. It's only been a month though, so this wouldn't happen for a little while yet.
I dare say by the end of the month we w ill be waiting on a very small handful of mods. Or maybe just the one.