@mos_8502 The only real limitation here is that it's hard to get inexpensive FPGAs in a package with so many physical pins, especially a more hobbyist friendly package (not a dense BGA, etc). Given that constraint, most pre-existing designs are tuned for lower pin count buses and more integration (there's plenty of space in the fabric for peripherals too).

PicoRV32 will fit in 1-2K CLBs and supports a very simple 32bit memory interface and a simple custom IRQ interface.
https://github.com/YosysHQ/picorv32

@mos_8502 Of the approachable Lattice ICE40 parts, if you want 44+ IOs (to allow 24A + 16D + control/cs/irq lines), and a non-BGA package, that's an ICE40HX with ~3K CLBs in a 20x20 LQFP144 package. ~$10 for singles at Mouser or Digikey. Not a lot of elbow room, but a minimal RV32I would be doable. There are a couple smaller parts but they only have ~1K LEs which is going to be very tight.

The more powerful ECP5 family has some 98IO 3/6/11K CLB 144LQFP options for ~$15/20/40 in singles.

@mos_8502 I guess I was just misunderstanding your complaint as a "I wish this was doable" (to which I feel like the answer is "it is, but not in a terribly optimal way") rather than "I wish somebody had built it and was offering one for sale".

I suspect it's a niche product -- wanting a more modern RISC-y CPU but with no integrated peripherals, a traditional parallel bus (but wider enough that many would find it awkward to work with), and packaged as a DIP64 footprint and/or castellated PCB.