Have you looked at
KJFAudio. They use the Hypex Ncore MP modules. You can spec four different modules of your choice. Their enclosure has fans, which I think is good, but your use case might be different. I also like the Neutrik sockets, which are the same as March Audio use, and look to be better than most other Ncore implementations with XLR and RCA with a switch in the signal path.
From reading various threads across the net, the MP modules are not quite as good as the NC500, but I‘ve never found any measurements to quantify this. From the Spec sheet the MP modules look good. The other bonus is the integrated Power Supply means there is one less thing for the installer to get wrong.
I’m thinking of replacing my Denon AVR-3808 for 5 channels of Ncore amplification.