Originally Posted by AaronP
Yes, you can configure a single X server to have multiple X screens on different GPUs and they will all have OpenGL support.
Thanks for the tip!
I had to change my window manager, because xmonad doesn't support non-Xinerama, multiple-screen Xorg setups. I use awesomewm which I configured to behave like xmonad, and it runs pretty good!
This comes at a cost though. I cannot move windows between different monitors, and I cannot have windows span across more than one monitor. I'll have to deal with it, but so far so good.