Have been trying out PearPC over the last day or so. It spent last night installing Jaguar, but it failed to boot this morning (hung saying "waiting for root device"), so it spent today installing Darwin, which worked (booted fine after install) and is now installing Jaguar again over the top of the bootable Darwin installation.
It takes a little while to install things on a 10 MHz emulated CPU :-)
Update (the following morning): it reset sometime last night, perhaps at the end of a successful install? Or because something went wrong? Whatever, now when I boot from the HD image, I get
JITC Warning, program exception: 00080000 00000000 errors forever. Oh well ...