From the top of my head i'd play him like this I think. Someone else come up with a point score
Tony "Can build it in a cave with just a screwdriver" Stark
WS BS S T W I A Morale AS/IS 4 4 4 4 3 4 2 10 2+/4+
-counts as Jump--infantry -equipped with 2 powerfists that double his strength but don't count as unyieldy and don't reduce I to 1 -equipped with a Plasmagun (his usual blasts) -equipped with a one use conversion-beam (the fancy red beam cutter from the end of II ) -May be taken as a HQ choice -all repair vehicle rolls might be rerolled
"I played with your toys a bit" Throw a D6 - on 5+ upgrade all Dreadnoughts to venerable Dreadnoughts for free. That's what happens if you leave him alone with a screwdriver.
"Red unz go fasta" This suit was an Ork trakk in it's former life - or at least the paintjob was. Add +1 to the maximum range in the movement phase.