I'm sure the design team at GM/AMG went through all this. To keep the vehical capable of what it does it is just not possible to put the spare under and hidden away.
We just have to deal with it, I paid the dealer to install the SMA tire carrier. I would prefur not to have it there but what can you do. Your options are to put on a tire carrier, put it on the roof, leave it in the trunk or stick it in your garage. You just have to pick what you can live with.

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'03 Hummer H2 Adv./Lux. Pkgs. Sunset Orange W/Sunroof
Air Spring Susp. Pkg. + 3rd. row seat & DVD System.
CompuStar Auto Security/Remote Starter.
http://www.haugens.com

How about a mount that uses the front hitch. Keeps it up high enough to not affect approach angle, low enough to see over? may work but I would have to put the washer and dryer outside Mine is gonna stay where the factory put it.

I debated back and forth when I was looking. I like not seeing the spare from the outside, but hate the lost room inside. I ended up going with the spare inside and now I'm glad.
I think I may do what some others have done and put it inside the garage. Just to limp home I'll hide a can of fix-a-flat in the cab.

If the Mrs. and I decide to take a long trip, I'll put the spare back in, but for driving around town, fix-a-flat should do it.