I had looked into that exact thing about a year ago - maybe more. I agree that the standard Bonnie tank would look great, but it would be some work. Apparently the standard tank has a two-holed mounting bracket at the seat end, where ours has a single hole for the bolt. Aside from the expected dimension differences, that's the big thing. If you can weld or fabricate otherwise, I say go for it. I'm sure the indicator lights from the dash would be re-mounted somewhere else easily, and I never cared for the plastic "chrome" dash anyway. Best of luck.
Keep the oily side down.
Tim