congrats on getting one of the largest mp3 players on the market... i am myself a proud owner of a 2007 tundra.
i have never looked behind the backseat of my truck but one this i can tell u for sure is that youd think that before my install i was sure there is planty of space behind the dash, and other places for just about anything... i was wrong, spaces in the front part of the truck are pretty tight... so i hope you find what you are looking for in the back (;
anyway i have also completed my install of a car pc... if u want to get some more ideas ... take a look... this is all the work ive done with the carpc on this truck...
2007 Toyota Tundra SR5 Carputer
UPDATE - Xbox thumbstick media control
good luck with your setup... i hope to see update on this, may-b i can pick up some ideas too (;