You're going to do a lot better setting an Ebay alert or searching Craigslist, nation-wide for a one-of-a-kind item like that.
Suggest you try "Daily Lister.com" to perform nation-wide Craigslist searches, maybe once a week till you find your part.
You might also get in some old manuals or parts microfiche and figure out if that same wheel went on any other Suzukis.
After that I might call around to motorcycle salvage yards like the one in Rye, Arizona -- or visit in person, as they're unlikely to know everything they've got on 5 acres of very old bikes. There's a thread on this forum of salvage yard addresses & phones you can search for.