Great info! The photos appear to show the truck handling the weight pretty well. No squatting? Did you add anything to the rear suspension?
Yeah, I agree, my trailer is a 26' (box) plus another 3 feet or so of hitch length. I wouldn't go any longer than that with an aluminum frame/fiberglass setup.
If the trailer is an aluminum skin over wood-frame, stick to something shorter, probably 20-22' (they are much heavier anyway).