Not sure if this is much discussed around here, or how legal this is - but there's a lot of information around online anyway.
Odometer data on most of these cars is stored on an 8-pin EEPROM inside the dash cluster. It's on the inside side of the board - so you'll need to remove the PCB fully to get to it. It's typically something like an 93c56 EEPROM chip.
Inside the chip, the data itself is stored in a certain way with checksums, etc that some people have figured out how to re-write the odometer data successfully - using an EEPROM programmer (like a TL866II Plus).
Having said all that, it should be possible to simply desolder the chip from one dash cluster and swap it into another dash cluster. For ease of swapping them - you could even put an 8-pin DIP socket in its place to make it easy to swap in and out in-case you needed to reverse it for whatever reason or it didn't work.
I can't say what other configuration information may be stored on that chip which may affect operation, and I've never personally done it - but if you're desperate - this is something you might consider.
This thread has some additional information that may help: