It will not be that simple. With so many different mappers used to manage
large memory, making one cart that does all would be fairly complicated. At
best wiuld be something like a PLC to handle the mappers and load the
appropierate one with certain game ROM like emulator and using RAM chips to
store NES ROMs. There are still a number of mappers not reverse engineered
yet, mainly on lesser common Japanese games and many pirated hacks. Also to
be able to store and manage multiple battery saved games as well.

Think like building an emulator program but using real NES hardware rather
than emulating PPU and CPU.

It would be MUCH easier to build a MAME type platform and just run NES
emulator using adapter to hook standard NES controllers to the PC.