Is there any reason you couldn't use a 10' section of real pipe?
Wouldn't have to make much of a hole for it
Should be a quick job for a post hole digger.
Two feet deep should be sufficient, as long as you put a big anti-spin cross-post down there.
Then, attach the upper end to near the top of the mobile home for stability.
Pole should extend two or three feet above the (flat?) roof, to allow clearance for the dish/motor.
Would be easy, reliable, cheap, cosmetically okay (no worse than a TV antenna mast).