I'm asking out of curiosity, if I'm to make that thing, it won't be anytime soon, if ever - but I'm curious if anyone before tried to build a '51-based Postscript printer driver - i.e. something you plug between the PC and the printer, if the PC sends something else than postscript, it just retransmits it, if PC sends postscript, it converts (executes) the file and sends in printer's own format.

With postscript printers priced 10 times what non-postscript printers cost, this could be a cheap solution to get your printer postscript-enabled.
(I recently experimented some in that language and found it to be a really nice one.)

BTW, what problems would I encounter, besides writing PS interpreter and printer driver? Certainly a chip with 2 interfaces (i.e. serial+paralell or USB+paralell) but I wonder about stuff like copyright issues, patents etc as well.