Unfortunately I doubt you will find any for sale mate especially here in Aus as the ADM models never got released with the USDM TT wheels as they only sold na drivetrains for all ADM models. The 44.7mm caps are also discontinued and I have never seen any for sale in the time I've been looking for rare Z32 parts (15+ years) and so if you do find a set for sale your very lucky indeed.
I also have the USDM TT 8.5" reear wheels and the centre cap is 54mm. For anyone interested in getting matching tyres for the front and USDM TT rear, Pirelli make the P Zero in both the 225 and 245 size but they are expensive. Tempe tyres imports them in stages. If the car is a weekender, they should last a very loooong time, probably expire before wearing out depending on how the car is driven.
I don't think the oddball rims I have are USDM Wheels, as they came off a JDM import years ago, here in Australia. I think the z32s that were manufactured in the month of FEBRUARY 1989, ALL had these oddball wheels. For z32s manufactured after MARCH 1989 ALL had the later style wheels. That's my understanding. Has to be one of the RAREST parts for the entire z32 platform. Any opinions?
After searching the world wide Web, I have found these oddball rims for sale in the USA. (minus the caps) They weren't very expensive either.