Timbo-
Actually, for the NACRA 5.0 I had for 17 years I had long 2x6's that were covered with carpet pads and carpet and it worked great for that boat as the bottom of the hulls were literally straight! Probably the "ideal" would be a flatbed of sorts as you suggest but carrying the boat upside down supported on the front beam and rear beam in the middle with high density foam beneath the entire front beam and middle of the rear beam with foam cutouts under the bows. That way the hulls are bearing down on the beams so no "hanging" of the hulls at all and no loadbearing except where hulls are designed for it. Only problem is the PITA one would have to go through unless you developed a simple/reliable system to "flip" the boat onto the trailer-

Kirt