Daniel said; "I've built one for myself from standard �" electrical 
conduit..."

Did you use rigid or EMT?  My guess is rigid, since EMT can be bent by hand, 
and might not be strong enough.  Although, you could use a bender and make 
nice curved corners....
Also, what did you use as a floor for this rack -- conduit, plywood?  And, 
how is it attached to the van?

We want specs and photos!!!