The LW Pro 630 fits on top but the rear door does not close. However, if the external plastics are removed, the internal mechanism does appear to be a fit. I have not gotten farther than that yet, and am not sure what I'll do about it.

I am into the whole vintage thing, but not the ghetto look, so I may just forego adapting a LaserWriter and use the HP printer as is once I find a Postscript SIMM (C3129) for it. They are such common printers that I ought be be able to dig one up locally if I give it time. Thanks for the lead on the cartridge. I will take a peek for those as well.