Phil, I contacted Show Wheels.
www.showwheels.com.au
They sell Intro billet 2 piece wheels. I was interested in Exposed - Sleek model. It's for a street car.
Just looked at those Budnik "fontana" wheels. Oooh, I like fat lips. Some nice styles there.
www.budnik.com.au
I'll be seriously chasing wheels next month. Not sure of your time frame, but can let you know what I find. Will look into some of the Jap wheels.
Simmons do not do a true 18" wheel, they use the same centre as 17", so will not clear my front brakes. Simmons are cheap for a 3 piece, but there are reasons for that.
I've got a set of 335/30-18 Michelin Pilot tyres
You might want to think about 13" wide rims with Kumho if they are the same spec as Michelin/Pirelli road tyres. The 12" rims don't quite stretch the 335/30-18's out enough. Both wear and tyre performance suffers when run on 12". 12" wide would be fine for 335/35-17's due increased sidewall height. Major manufacturers always run 335/30-18's on 18"x13" wheels.
You know your performance on track will suffer running that large a rear tyre on a Cobra. My brother gets hounded for running 255's on rear of that Harrison by race tyre shops, they reckon they are too wide for that car. He seems to get enough heat into them, so maybe not.
Your Cobra would look fantastic from the rear with those tyres. Got a couple of Cobra's up here than run 315/35-17's and they look tough.