Anyway, I totally forgot to answer your original question but I'm far too lazy to Edit my post.
I don't feel there is any game on a similar scale to Outpost 2. The major players of the RTS world (StarCraft, C&C, Civilization) are far different, with Civ probably being one of the closest you'll find. I can't vouch much for indie RTS games, but honestly after the huge flop Outpost 1/2 were in the eyes of critics, I can't imagine a similar formula being sought-after by anyone who'd get much media/critic/consumer attention for developing such a thing.
Unless it was pulled off in such a strikingly similar but radically different way. You won't see "OP2" clones, that's for sure.