This blog is pretty good for keeping an eye on interesting stuff.
As for SupCom, I'm not really that into the RTS scene these days(SupCom was awesome, though). Starting off with the large-scale RTS, I can think of Sins of a Solar Empire, then you might want to check out Gratuitous Space Battles, AI War, Darwania and Defcon.
Maybe someone else has more suggestions.
EDIT: Throw Harvest: Massive Encounter, Massive Assault and Star Ruler on that list and keep an eye on Achron, just the trailers blow my mind.
EDIT2: I'm finding new stuff for myself as well now, APOX looks really cool.