I have an older 360 with a xenon mobo, toshiba samsung drive and NO hdmi out. I have updated dash to kernel 2.0.14719.0.

I wish to mod this system with a chip or softmod to run homebrew. Having searched and read many guides and posts on this site and others I have come to the conclusion that this is not possible. Am I wrong?

You could try RGH but they say that xenon are highly unreliable so you probably better off finding a system that is before dash 14717 and RGH it because RGH2 isnt so reliable. You could also get a slim with dash 14719 or earlier and the slim has to be made before august 2011.

You are correct. The only reason people RGH xenons is to recover the DVD key if its lost. It is otherwise too unreliable to be a permanent modded system.