With a Dually I assume your looking for a Fifth Wheel? The top of the line Toy Haulers have a top of the line price as well, $70k to 100k...
If I was buying today I would be looking at the Amped 32gs. It's not a Fifth Wheel, I just like the looks and Fifth wheel floor plan in a bumper pull Toy Hauler.
http://www.floydsrvs.com/New-Inventory-2015-EverGreen-Toy-Hauler-Amped-32GS-Norman-Oklahoma-812209You could put the Razor in the garage and the dirt bikes in the back of the truck! The one I looked at was washer and dryer ready as well.... I don't think you would get two dirt bikes and a razor in a 12 foot garage..
OSB is being used in the home buiding industry more than plywood as well. OSB is cheaper but has a stronger shear rating...