Co-op RTS games like SC2 Commander / DoW2 Last Stand?
Title. Lately, I've been losing interest in playing PvP games in general, not just in RTS, and have mostly been playing skirmish and co-op in games that support them. For me, the height of co-op in RTS is Starcraft 2's Commander mode and Dawn of War 2's Last Stand mode, due to how I can gain XP, level up my characters, and create a unique build. Are there any other RTS games with co-op, ideally with public matchmaking and an active playerbase, so I can just jump in and stomp bots with random pubbies?
To be clear, co-op CAMPAIGNS, like in DoW2's singleplayer and Command and Conquer: Red Alert 3, are NOT what I'm looking for. Those are cool and fun, but they're clearly designed for long-term play rather than quick pick-ups; none of my friends are interested in RTS games (they mostly play RPG's) and I don't want to commit to meeting up with people in Steam Groups. I want to be able to jump in, play a few matches, then hop to something else.