As far as I understand it, Vegas with Whyte Laydie and Tubaphone tone rings are good candidates for conversion but the end product will be a banjo best suited for old-timey music rather than a bluegrass instrument where the Gibson Mastertone design is pretty much the standard.

If you do go down the conversion route, be sure to keep the tenor neck so that the instrument could be put back to original at some point in the future.

Jon