I know of FPGA based implementation of whole Amigas [1] and I do not htink they are particularly expensive. It is very likely that SNES reimplementations also exist already.

Edit: this [2] is a full system for 220 euros and in addition to Amiga it emulates a bunch of 8 bit consoles.

[1]: https://en.wikipedia.org/wiki/Minimig

[2]: https://amigastore.eu/en/358-mist-midi-fpga-computer-with-mi...