John, I put 17" Mercedes rims on my 88 Vanagon. I had custom hubcentric
spacers made at www.wheeladapters.com. 10mm in the front and 14mm thick in
the back. They were $65 each. I had to get longer studs for the rear wheels.
Very happy with the result. I have some photos at:

http://vanagonproject.page.us/wheels.html

The web page is a work in progress, so excuse all the broken links and
incomplete sections.

Mike