Spideroak supposedly offers that, but it's still U.S. based. They haven't open sourced their client (they've stated they will) so it's hard to completely verify.
If you want to host it yourself there's Seafile but I haven't seen any in-depth review of it and it's Chinese-based (if that's a problem [for you]).
I really like SpiderOak I have been using them for more than two years. Resent update added a true dropbox experience. And most importantly it has a client for Linux, OSX, windows, ios and Android.
If you want to host it yourself there's Seafile but I haven't seen any in-depth review of it and it's Chinese-based (if that's a problem [for you]).