RoadRacer- I would guess that anyone who can weld aluminum could build you tanks. That is... if by ends you mean tanks.. not just the inlets.

slaab- No one around here has a mandrel bender. Your best and cheapest bet would be to grab a JC Whitless catalog (or go online) and order some out of there. They have all sizes and radius and are pretty damn cheap. A little creativity cutting and welding and youre done.