The breakout boards themselves are still in stock on Parallelminer- you can opt to buy those and 6pin cables to attach onto the boards and buy the PSU separately, perhaps from eBay. It's only the complete kits OOS atm.
Alright yeah I see what you mean, so any server power supply should work with the breakout boards correct? Or is there a certain type of server PSU that is required for these breakout boards?
My response is a bit late, but the breakout boards should specify which server PSUs work in either the title or in the description of the product. Not all server PSUs work with all breakout boards.