straytech and linuxqanda, thank you for your responses and suggestions. linuxqanda, I looked at both of those pages, and they are both ones I tried to utilize before, with no success.
I did end up getting my system to boot from RAID 0! Here's the details of all I went through to get there.
With only the two RAID 0 drives, I tried every LILO setup option I could think of. I tried the append statements in the readme file attached to the Promise drivers. Using quasi software/hardware Promise RAID, Linux just won't boot (for me at least!!!) from a RAID 0 array. I was using the ataraid.i Kernel in Slackware 10.1. I know it is the correct kernel, because if I booted from a floppy, everything worked OK.
So, I installed a third hard drive on the primary IDE channel, thinking that if I put the boot directory and the MBR with LILO on that drive, and then put the / partition on the RAID array, it would work. Even though the kernel saw the RAID array as /dev/d0, it still also saw the two RAID drives as ide e and g. LILO still crashed on install, because the ide e and g drives didn't look accessible. (they're striped, and don't work individually).
Next, tried passing the kernel options to noprobe ide e and g. Got a little closer, now I had a Kernel panic.
About this time, I realised I'd spent close to a month on this. Not a total waste of time, as I learned a lot. But still a waste somewhat.
I bought a new RAID controller. A 3Ware 7006-2. I installed it, and removed the extra boot drive I'd attached to the primary IDE. Spent 5 minutes figuring out which kernel to use in Slackware. The raid.s kernel has the latest 3Ware driver precompiled. Loaded up Slackware. It worked PERFECTLY!!!! Slack sees the 3Ware as a SCSI controller. LILO even auto installed with not a single issue. The whole system is faster, as the 3Ware is true hardware RAID, not a Ken and Barbie quasi software RAID. I am booting from RAID 0. I am happy once again!