My last bumper tow toy hauler was a Coachman Adrenalin, 32 footer.
It pulled like a dream and you would have thought it was air ride it was so smooth.
Three axles is a must, they ride smoother and the stability cannot be beat.
Also the load factor on each axle is reduced, that helps in the tire heat department.
The only other toy hauler I've had was the fiver we recently departed with for our DP.
For the hauling capacity, and as you mentioned no frills but full function, the bumper pull wins hands down.
I could but never did, put six full size motor cycles in the Adrenalin, but only two in the fiver.
That Adrenalin model is very hard to find as I suppose people don't want to get rid of them. I'm sorry I don't have the exact model number handy now, but that's just one name and brand you may want to take a look at. I'm sure it would be the perfect example in your search to gauge your needs.
Dan & Loretta, US Army Retired Aero Scout Pilot
2012 Fleetwood Providence 42P Class A/DP
Spartan Chassis, 8.9L Cummins 450HP