Razz0putin said:
I know Paizo is staying with 3.X
Only for the time being - and actually, they're moving to '3.5+' (i.e., their own
Pathfinder RPG.) Whether or not they produce anything for 4e, and if so when, is AFAIK open to speculation, as most things are. But that's about it.
but what other companies have openly said that they'll stay?
None, that I know of. Not explicitly, with any kind of 'forever' claim or promise, at any rate.
There will be companies sticking with their own d20/OGL systems (e.g., Spycraft, True20, Conan, Mutants & Masterminds, Iron Heroes, Arcana Evolved) - but not, even then, necessarily 'in opposition to' 4e. IOW, they might do some 4e books too, some time down the track.
What's causing some concern and confusion atm, other than the great big honkin' edition shift round the corner of course, is the delay in the GSL's release, and hence the weakening value of the that $5000, so to speak. Potential early adopters are losing out day by day, er, potentially. This might have influenced with Paizo's most recent decision, for instance. I don't know, just guessing that it had a part to play anyhow.
3e, or some form of it, might survive, and even thrive, for years to come. The way things are, on more than one level at the moment, I wouldn't be shocked to see that happen.