I know NeoAxis, which uses OGRE as graphics engine. It's a nice engine but has no Source Code with it, which limits the flexibility of itself. Unity takes away features I require and has no source, unless I buy the 1500$ license. Source is pretty nice, but the SDK is pretty much outdated since it's been the same since Half Life 2's release.
Bluefury, Source engine allows you to make a new game:
http://en.wikipedia.org/wiki/Category:So...gine_games
UDK was removed as an option because of the simple fact that it takes too much time to build anything on it and has too high specs.
I appreciate your help anyway. This is really an hard decision and the only way to make it is to get other people's opinions.
Today I dreamt the life I could live forever. You only know that when you feel it for you know not what you like until you've experienced it.