I assume the cross-brace that actually holds the bikes is what you are naming as the "MXporter". Everything else is mounting hardware correct? Just trying to get the normanclature straight. Assuming yes, then:
Obviously, the floor mount in a open trailer is the only available option for me. I would be open to the idea of "semi-permanent" floor mounted bases that upright "stanchions" could be inserted into. Then the cross-trailer MXporter could be mounted to those. I'm interested because I need something better than what I've been doing.
The inside dimensions of the Triton UT10 is 6'4" (bed width). Assuming the floor mounts and stanchions would take up some room also. I would need something very similiar to the 3-bike enclosed trailer MXporter, but with custom endcaps (because I would be mounting to stanchions, not walls). What kind of cost would I be looking at for something like this (an estimate). I won't hold you to the dollar if I decide to do something

.
Also, I assume this would be for full size bikes. Got anything for the boy's CRF50 if it's just him and I? Or would I be strapping the 50 in normally?