well a standard din size is a smudge over 2", so yours will be a double din.. so you wont have any probs with the housing and a cdplayer. As for the xbox.. The ports on the xbox are usb, so you could just extend these cables and stick em at the front.. I would love to stick my xbox in my car.. just not much room. I might have another go at loading linux on it sometime, I'm sure it will have improved since my last attempt over a year ago.. :-)
I have a TM-701L housing myself, to be honest i'm not that impressed with the quality of it, theres no way of holding it in to the din (no sleve) and the screws holding the front bezel on. (this stops the screen coming out too far) is held in by 4 tiny screws that are poorly fitted. I'm looking for another housing at the mo.. expected a half auto one to come tomorrow.. so will have a report tomorrow night. :-)
I would prob be tempted to look for another screen. one that at least will enable you to secure it in to the din slot.. look here thats what i've ordered..