find a local guy (usually just out of the cities in the rural areas) with a WELDING sign in the front yard, talk with him.. 
goto Home Depot buy 2 10ft lengths of 2" rigid electrical conduit, 4 90' bends and at Kamart/wal-mart a STEP BUMPER 2" square reciever.

remove your old bumper but salvage the parts that slide into the bumper mounts pocket, 

have your new welder friend shorten the 2" rigid pipe to the right length, add on the pricey$$ 90' ends (mostly for a finished look
and weld the step bumper 2' reciever inbetween the 2 pipes (with a lil bracing for support/sturdyness
and for about $100+labor you have a very nice and heavy duty (won't crush your corners if the Mrs backs into a post, bumper) (the extra $40 in 90' bends is added corner panel insurance)

goto a u-haul, RV-mart, or large boat sho and buy a 4wire round plug receptecle and plug, mount it flush in the back panel near the tail lights and wire accordingly.. 

even pep-boys has the 4pin round plugs.   

wire a marine cigarette 12V power source back there while your at it.. 

1 more thing that I'd STRONGLY recommend to add to the back panel. is available at marine suppliers it's called a FIREPORT and is a clear circular portal with a Hightemp site window that opens for allowing the application of a fire extinguisher in the event of an engine fire without havingt to open the engine lid,  this may save yoour van, 

Dan

Date:    Thu, 2 Oct 2003 19:27:17 -0700
From:    zolo <zolo@FOXINTERNET.NET>
Subject: After market rear bumpers?

I was wondering if any of the vendors carry after market Vanagon rear =
bumpers and their parts.
Zoltan