Good luck with getting the upgrade kits. Yes, hopefully these will become available again as the 1963 Lotus 29 kit has been reissued.
Personally, what I'd like to see are new(er) Indy car kits become available. It'll never happen, though.
I had contacted Michael back on July 2nd concerning these kits, and he said that supply shortages on resin casting materials is slowing production down. He also said that there was a high demand for these kits, so hopefully once he gets his supplies he'll be able to cast more.