I downloaded the Nsim emulator (the only one, it seems, that will run on Unix/Linux) and compiled it. However, I don't have a ROM in the format that it wants. All the HP-41 ROM images I have are in raw binary or p41 format, and the simulator wants a text file with ROM addresses and ASCII hex values, one per line. I can't find any conversion software to do this (there's a format converter for Windows, but it doesn't seem to support the format I need among its half-dozen).
I can whip up a converter to do this without too much pain (though it'll either run on Mac or Linux -- I don't have a Windows box at home)... but if someone already uses Nsim and has the ROM file in the proper format, I'd be indebted to you for a copy.