Turned out really great!
I took the ATV ramp, cut it at the center hinge (it folded over onto itself in half), and added aluminum pieces in between, as well as two bigger aluminum supports that attach to the Garvin roof rack feet. I can stand on the rack in the middle and get very little flex (all 220 lbs of me).
here is a short little video where you can see the rack well:
https://goo.gl/photos/EoRRho2mwhPULjCH9
some stills:
Test Fit, before paint:
https://goo.gl/photos/YmNmRn38L4vAR3t49
Cross Support - the end of the cross support has a solid block of aluminum jammed into it so that the tube isn't hollow there. Allowing for the bolt to be tight and not crush the tube.:
https://goo.gl/photos/bE2dUbVoT14dAaKUA
This shows how the cross supports and the rack align. I really like how low profile everything is. Only the very outer tube on the rack isn't supported by the main supports, but they are supported by secondary supports in the middle (this is before the solid aluminum was inserted into the end of the cross support):
https://goo.gl/photos/nUFf3B8TPTMAtBHy6
Had a friend help with the alum welding. You can see the two pieces of the ramp spread out. We put everything up on the montero exactly how I wanted it to sit, tacked it in place and then pulled it all down and welded it together:
https://goo.gl/photos/t6VQdvQ9qvRWefXW6
This is the ramp flipped upside down. You can see the two main cross-supports where the Garvin feet attach, and two smaller supports in the middle:
https://goo.gl/photos/SrTmpwzfbYrFz7Kz9
After a few coats of paint:
https://goo.gl/photos/zbW3BN5TkPUYnX2YA
For the front air deflector, I bolted on a piece of aluminum sheet, rounded the corners to match the radius of a pringles can and cut it with a hack saw:
https://goo.gl/photos/kAD9w9a8H3Hu4WxA6
Fully assembled:
https://goo.gl/photos/Mxs9RXNk8MDRuMMy9
If I had to do it again, I would have made it the full length of the top.
I've also used the rack to transport drywall, plywood, and lumber from the home store.
it's also a super great area to toss sleeping bags, tents, action-packers, etc, etc, when you get to the camp site and don't have a clean place to put things, but you need to unload some items from the car.