A friend of mine has a tri-fold ramp that is as wide as the tailgate on his lifted F-250 diesel and he rides his bike into the truck bed. But then again, I think he's a little off too! I trailer my bike on a small utility trailer, about 4' x 8' tilt-bed with no gate, using a wheel clamp to lock down the front wheel. I bought the trailer used from another riding buddy and he had bought it new from up in West Branch. In my opinion, any well-made trailer will do. I prefer the larger wheels w/ bearing buddy's for ease of maintenance and roadability.
I use a short ramp made out of a 2" x 6" and one of those ramp brackets instead of the tilt bed more often than not. My other option is to pop the front wheel and allow the rear to climb up on the trailer.