Hi Well, Her Majesty's empire really came through for me! Thank you to David and Frank for your help.
Frank was right about booting off the non-BIOS SCSI disk...for some reason, it does work (and, as he hinted, the magic incantation to LILO seems to be "linear"). I did not end up needing to try loadlin, though that looks like a fine solution. Incidentally, because I share this box with others (hence my hesitation to touch the IDE drive), I wanted something a little more user-friendly in the boot loader. I had an old copy of System Commander around, so I tried installing it. It would not see the second drive even though LILO did, but it has an option to boot from a MBR saved to a file. So I used "dd" to save the LILO MBR to a file on the Dos/Win partition. System Commander was then able to boot Win98 directly, and to chain-boot LILO. Thanks, guys, Brian