very similar in spirit to Olimex Neo6502
https://olimex.wordpress.com/2024/06/25/the-world-fastest-65...
it's a real 6502 assisted by a RP2040
it's a real 6502 assisted by a RP2040
I think the only thing that really holds the original Propeller back in such projects is that while the Propeller is fast, it's going to take a few cycles to interface the 6502 bus whatever you do. The Propeller runs at 20 MIPS per cog, which can easily bit-bang the bus when the 6502's running at 1 megahertz or so. But if the 6502 is running at 16 megahertz then it's not going to be able to keep up without some external decoding logic and throwing in a wait state via the 6502 RDY pin.
The newer Propeller 2 would have no such constraints, but it's also a more complex chip that you can't get in a 40-pin DIP.
A small board could sacrifice some IO pins and still get it to 40 pins. Or, at least, 64 like a 68000.