Just have too many projects going on, and I really like my Modelo. Nothing else.

What you are asking for with the 9mm chamber is already finished and released. It's called "the 9mm deep". It's available on BLC odyssey. There is someone who got it to cycle in a modified FGC9, but I would totally wait for the 9mm decker to come out, as it works better with printed ammo than any of the FGC variants. The biggest change to be made is bolt weight.