I've decided to go with proper flat track tyres... which means 19" front and 18" rear rims. Which means I can't run the TZR wheels I was going to use. So I hit ebay and got a set of TDR hubs for not a lot of money. I intend to get them blasted and powder coated before getting them built into a set of alloy rims using stainless spokes. I expect this will cost considerably more than the hubs.
Oh and the front is for a different (larger) spindle so I need to machine up some adapters.