Trans Am Race Engineering Superlite 17x8 - now available with a useful backspace?
edit:
Actually I noticed you can still get the off the shelf wheels for $375. If you can make an 18x10 work with a 6.25" to 7.5" backspace you can get the ETIII's for $375 each.
And actually I think that might work for some folks, on my car I could pull off an 18x10 in the front with about a 6.6" backspace, and my 18x10's in the back currently have a 7" backspace with the '70 B body 8 3/4.
For a Demon/Duster/Dart Sport it would be doable, on a Dart in the back an 18x10 would be pushing your luck with the stock tubs, even with a 1/2" offset. Still need a wider rear axle though.