Joe:
I really wish you lived closer to Portland.  I'm on the verge of buying a
110v Mig Welder Outfit and your need for a weld would be one more reason to
convince myself to get one!!!
If you were to remove the seat, peel the carpet back from the weld areas,
drape some protective cloth over the areas near the welds (up to 3' away),
and tell him you would take care of wire brushing and painting the welds
afterward, he should be able to finish the job in fifteen minutes.  And
that would cover his time wirewheeling the weld areas in order to clean
them before welding.
I'm sure he'd do a good job but that seems a bit steep to me.

Best of luck.

Brent
www.weidefamily.net/vanagon/