ive seen a bloke just cut a hole out of his tray floor, i think it was opposite side of the fuel tank and weld up a box to fit it.

there was also another one that x member Smurf did, DDgonzel might be able to show you that one...

I think Gylezy (doesnt get on here much anymore i dont believe) had a well designed one in his ute build thread, check it out..