Here's a link to another xtera thread on the forum I'm not sure how to link it
http://www.gbfans.com/forum/viewtopic.php?t=33889 I would suggest getting a roof cargo basket simmilar to this
You can put attach all the goodies to it and have it removable if needed. Attach the hoses to the basket and have them magnet to to the side of the truck
You don't necessarily need full light bars as a strip of tri colour led tape shining through a piec of frosted plexiglass would provide a great effect and can be programmed for different sequences.
Keep it light (check your max cargo capacity)and waterproof and make sure to securely bolt everything (use nylons nuts
Hope this helps have fun