Trailer rules basically come down to taking the engine rating, applying chassis mods, then dividing by the total mass. If everything's tracked, there's no chassis mod.
So unfortunately, a 1/2 movement rate on the tower won't quite cut it. If you go 2/3, then the engine rating is 400, so a 200-ton tractor could haul up to an additional 200 tons at 1/2. A 3/5 200-ton tractor could pull another 100 tons at 2/3, or an additional 400 tons at 1/2.
Short form, tractors need surplus engine ;)
And I have no problems with having aux power on trailers; it's just that HMVee enforces 0 engine if you tick the trailer box.