That's the general idea behind this project:
https://github.com/nonarkitten/amiga...cement_project
I don't know how far along they are, though.
The biggest problem from a hardware point of view is just that 5v-tolerant FPGAs aren't exactly common, so any particular board would need to include level translators.
Also note that the Indivision ECS scandoubler effectively re-implements Denise in pretty much the way you have in mind.