The BBT just dropped off my new steelies from Tire Rack (one day
shipping time!). Stock wheel bolts go through just fine, and seem to
seat just the same as on the stock wheels. The centerbore was not an
issue, either.

They have what appears to be a part number, KSW16028, on them, but no
luck finding who makes them.

I mounted one, and clearance seems perfect, there should be no problems
with a 215/60R16 tire. I put some pictures up at
http://www.flatsurface.com/vanagon/16wheels.html

Off to order some Falken Ziex ZE-912 215/60R16 99H tires...