Just sniffing around a bit I found that:
www.wheelsnext.com has rim by R-1 called "GTR-7" that looks similar. Also Drag makes one called a "DR-6" and Katana has their version named "GR7".
Tenzo's clone is called "Drivex7" but is a little more expensive then the other rims I've listed.
If you can find a new set w/ tires for under $2000 I think you'd have found yourself a good deal. Not sure of the quality of the "clones" but I'm assuming they're casted, heavier, etc. then the Ray's Eng. version.