According to Aux.tv, a whole bunch of unreleased projects by PRince have been uncovered, and among the 99 items, a Transformers-based album has popped up, under the title of Pure Energon, along with new wave/dance band Information Society. That is all there is for now, but we do wonder if the album will ever make it in any form to some sort of release!
Pure Energon — Transformers-themed concept album with the Information Society.
UPDATE: Take this news as even more of a rumour as you would have initially, as the list may in fact be a catch-all piece on popular properties that people would like to see in Prince's vault. Perhaps a fun tidbit, as pointed out by Nerdist site, here.