or perhaps someone knows how to make a cart to play these on an NES ? I have seen the NES Reproduction site with these carts, but I'd like to either get thme working on the PowerPak, or try making my own repro carts.
Apart from A) the PowerPak's predictable initialization and B) any errors in the mapper logic, the PowerPak will preform EXACTLY the same as a "repro". If the games don't work reliably on the PowerPak, they probably don't work reliably in a "repro", especially since without a doubt the PowerPak's UNROM and MMC1 mappers are OK.
I got them to work after all. I updated my ROM set and the versions I am using seem to work just fine. Interestingly enough, a lot of games on the nesproduction.com site actually work on the PowerPak like Kart Fighter