I put mine under with a quick release pin on one end for access. Painted black since the photo so you cant really see it.
On our front set up. The tank, crate and battery sit on angle iron thats welded (i asume) from the factory. I added the crate for my blocks etc but could run a second tank there if needed.
*Currently trailer-less but shopping
07' GMC Envoy w/ P2 controller (current TV)
88' Chevy K5 Blazer (soon-to-be TV)
74' VW Superbeetle (1303)