Well,
Without going to the extremes of telling you which model is flat towable and which one is not, I'll leave that to you but, putting only a 400 + lb. motorcycle in the bed of any smaller pickup is no big deal. We tow our '11 GMC Sierra 1500 4x4 extended cab and, when we think we'll be wanting the bike along, I quickly put in our Rampage lift which takes around 4-5 minutes. That lift then pulls our '08 Honda GL 1800 Goldwing right up and into that bed. A few minutes of adding tie downs and, we're off to have fun.
He's probably still on here but, there was a member who towed a Ford Ranger with a full sized Harley touring machine in the bed of it. It worked flawless for many, many miles. All he did to compensate for the heavier weight of the Harley was add a couple of air bags to the rear of the truck. When the bike was in and loaded, he just added a few lbs to the bags and, that truck was completely level.
But, we don't do that with our setup. Yep, ours sags about 2.5" or so but, no big deal. It tows just fine, tracks right behind the coach with no issues, no wandering, nothing. Heck, there's times when we're only going to be in a camping area for a single day so, unloading the bike is not warranted. When that happens, we still drive the truck around WITH THE BIKE in the back and the truck handles flawlessly. Of course I don't go road racing with that load in the back and, am aware of the additional weight so, we're careful.
But, you'll have no issues with that small load in a smaller truck. Go find the one of your choice and, get the bike in there and have fun. Now, getting that 400+ lb. bike up there, well, you're bordering on DANGER here in the fact that while 400 lbs. on the ground and handling it riding around is nothing at all.
But, 400 lbs. in the middle of a ramp, 1/2 way up that ramp, is UGLY! I don't care how many say: "It's no big deal, just ride it up the the ramp or, find a dock someplace to back up to" and you'll be fine. If that 400 lbs. falls while trying to load it, it ain't gonna be pretty and, the potential for injury skyrockets. So, however you do it, just do it safely.
Scott