@gsohler, please, (REALLY PLEASE!), read through this article a few times => http://xboxmediacenter.com/wiki/Linux_port_project
That article describes what the "XBMC for Linux" (Linux port of XBMC) project is all about, including set limitations and boundaries.
The "XBMC for Linux" (Linux port of XBMC) will never be supported on an Xbox! ...even if there was OpenGL 3D hardware-accelerated device-drivers available for the Xbox (which there are not); a full Linux operating-system has too much overhead to run XBMC for Linux on a 733Mhz Intel Pentium III processor with only 64MB shared memory (shared memory meaning that the Xbox only has a total of 64MB memory which is shared between the graphics controller and the system).
@gsohler, other than than we really appreciate your enthusiasm about XBMC for Linux and ambition to submit patches for new features, but you/we have to be realistic about what platforms it will run on. If you like to run XBMC on your Xbox game-console then use the native Xbox version and built a separate Linux PC on which to store you media files (audio/video) and share that over the network (that storage server can be a older PC), however if you like to consolidate everything into one machine then that machine should not be the Xbox, instead go for a better more modern PC which can handle the multitasking load that you require.
Thanks for listening and understanding.