Other than fan projects, I'm not actually very familiar with post d20 Modern d20-like systems.
There's Spycraft which got a lot of attention for a while. I think it was a bit more crunchy than d20 Modern. There's Grim Tales, which is more of a modular toolkit for Modern, future, post apoc, or all kinds of other genres.
I think there was a fan project to convert Star Wars SAGA into a d20 Modern-like game, which might have been pretty cool, but I don't remember seeing it ever get completed.
:shrug: I'm with you there, and I'd be curious to see something else. But by and large, I'm still just sticking with d20 Modern, and I haven't yet found anything that's obviously so much better that it would convince me to switch over.