Mel,
If you are still interested check out
www.corvette.com.au They don't do jeeps and they are in Queensland but you can get a feel for the price of a conersion (12 to 20K).
I also lived down the road from Superformance in Brisbane for a long time and they always had converted Chevy trucks. I contacted them several months ago and they had just got out of the conversion business as new lawsws had made the conversion business cost prohibitive.
Hope this helps.