[DJ_Izumi]

Yes its possible. Open the zip file and edit default.py and in the second line remove

taskkill /f /IM XBMC.exe &&

. But launching games and emulators over xbmc has always give me problems - xbmc accepting controller inputs while games are playing, games/emulators having no sound, xbmc not getting focus on game exit and xbmc using a significant amount of cpu. Do you not get this problem?

I would try changing the second line in default.py to this

os.system('taskkill /f /IM XBMC.exe && timeout 1 && E:\Steam\steam.exe -bigpicture && timeout 1 && C:\path\to\XBMC.exe')

to have xbmc killed, steam launched and when exited xbmc is relaunched.

Keeping XBMC in the background doesn't seem to make any noticeable influence on game playback on my machine, A8-3870k with 16GB RAM. I run XBMC in true full screen so it minimizes to the background. I stripped your script down a lot however, I was already using a batch file with nircmd to have Windows do a force focus back to XBMC when Steam closes. I actually just cut your script down to do nothing but execute that batch file. I found one hangup that you may want to specify in your first post however: You don't JUST need to write in the location of Steam in default.py, you ALSO need to do it with 8.3 file name conventions.

c:\program files (x86)\steam\steam.exe is no good for example, it has to be c:\progra~2\steam\steam.exe or else your script only tries to execute 'c:\program' and stops there. Once I figured this out and figured out the 8.3 conventions, it worked fine. I imagine you didn't notice this yourself because your steam location uses folders/filenames with only 8 characters and no spaces.