Rex;
I was faced with something vaguely similar. My rear hubs were Porsche 996 with a 5 x 130mm bolt pattern and I couldn't find any Porsche wheels with the size (diameter, width, & backspacing) that I needed. A bit of scale drawing showed that the 130mm bolt pattern was close enough to the circle track standard 5 on 5 that the hubs could be easily machined to accept 5/8" wheel studs onto where the existing metric holes existed before.
If there is a chance that you could machine your hubs to a 5 stud 5" diameter circle, you will then have the opportunity to use circle track racing wheels. These are inexpensive and are available in lots of widths & back spacings. Most are 15" wheels but there are a few other sizes. Look at Bassett, Aero, Marsh, Speedway Motors, etc.