I spoke with one of Ultimate Sole's distributors in Canada yesterday and asked him if they carried it. He kind of chuckled and sighed and said that they were restructuring the company and that it WOULD be available again sometime (no specific idea when) in the future. Why they're not getting the word out is beyond me ... I sent them an email and it did NOT bounce so it's sitting in someone's inbox.
I also asked him what was compatible OVER Ultimate Sole (I probably have enough to do mine) if it isn't available in the future and he said "any varnish".