@ Steve
Have a look at the VSL [Vienna Symphony Librayr] Ensemble Pro 5.
It acts as a host for AU/VST/VST3/AAX Native/RTAS instruments…The software connects your main DAW to plug-ins running on your slave computer. All Midi and Audio are done via ethernet. You can use 32bit and 64bit plugs.
VST3 supports up to 48 midi ports [ie 48 * 16 channels!!], and 768 audio ports!! Comes with Epic Orchestra - 9Gig orchestra sample library.
Cheers