Another $0.02.
        I always like to be able to get into the engine compartment/rear 
hatch easily, so I use a front mount. I have a regular bikerack, for the 
rear trunk or hatchback on a sedan car, RhodeGear model, pretty universal 
style. It is adjustable and can be opened out fairly flat. The bottom of the 
rack just sits on the lip behind the bumper, top rests against the nose, 
under the wipers. On the '78 I cut small notches in the air vent grill to 
allow the anchor straps to get a good grip inside, on a cross piece. The 
lower straps hook onto the bottom edge of the bumper.
         I like seeing the bikes out front, and if they come loose then I 
get to run over them first, not some stranger! The system is really solid, 
since weight bearing is done by the rack frame resting on the bumper, not by 
the anchor straps. On the Vanagon the upper straps and a cable lock go 
through the upper grill, the cable lock comes out the lower and keeps things 
safe. With two mountain bikes it works fine. The bike wheels are below the 
bumper however, so curbsurfing etc. should be avoided! 
        BTW. Has anyone ever seen a bike rack fashioned to fit on/where the 
front spare tire carrier plate is on a breadloaf? Might serve two tasks 
neatly, easier to throw the spare tire in/under the van than bike(s) when 
camping.
  tim s.