If you are talking specifically about the world of Glorantha, then no. Greg Stafford has made it quite clear: no D20.
Hasbro owns the rights to the name and the game system Runequest, but Glorantha was transferred back to Greg Staffords' Issaries, Inc.\
Personally I prefer the BRP system, but I have no big love for the 3rd Edition RQ game system as a whole (it did make some improvements, but added alot of needless complication).
I think the chances of seeing RQ20 are as good as seeing DragonQuest D20 (another really cool FRPG that TSR ended up with rights to after they bought SPI..then they screwed it up, then buried it..Unfortunate..it was a very cool game)