Here's my on-the-fly notes, with links to where I found the information that helped me solve my problem above.

I like to keep my data on a separate drive. As I formatted my entire BootCamp partition as NTFS for data robustness, it is READ ONLY to MacOS. I eventually want to run Parallels, so it would be good to have my data on a separate drive. I tried installing Acronis Disk Director 10 under XP, but the partitioning scheme used on the Mac is newer than what's used on XP; it's nicely documented here as part of another article. After looking around for partition resizing utilities, I came across this article about diskutil, the built-in partition tool for MacOS X, now adding resize support. I'm about to try that, after purchasing and installing Parallels.

And here's another nice reference on one person's experience using diskutil

Ok, after re-installing MacOS X to undo the partition madness, then updating, I tried running BootCamp Assistant. It promptly told me that I couldn't run it. It installs a BOOT MANAGER to allow windows booting. So I'm going to nuke the other partitions and see what happens...it INSISTS on being the one to diddle everything together. Annoying.

So I had set up the 250GB disk as 60GB Mac, 60GB Windows, and the remainder for DATA. I used Disk Utility to delete the Windows and DATA partitions, leaving the 60GB Mac partition. When I ran Boot Camp again, it saw ONLY the Mac partition, not the empty space. Hmm.

So I loaded up Disk Utility again, and doubled the size of the Mac partition to 120G. I then ran BootCamp Assistant again, and choose DIVIDE EQUALLY. This, I believe, locates the Bootable Windows Partition within that first partition in a way that will make the system bootable.

Upon reaching the Windows XP installation area, I was troubled to see that the unpartitioned space I'd left was nowhere to be seen.

So I started again. This time I used Brad-X writeup on the process, which was similar to the MacWorld article in its material, but coupled with the previous insight made me realize there was something special about the resizing process itself. In the process of resizing one of the already-partitioned disks, I think this somehow preserved whatever structures needed to be preserved. This is purely a guess though.

On following the resizeVolume, I made sure I had the right partitions in the right order: Mac, Data, and Windows. The Windows partition, according to what I read online, HAD to be the last partition. I believe this is a physical layout requirement. The new partitioned showed up (yay) when I launched Windows XP Installer (holding down the C key to force boot the CD-ROM). However, the Windows drive was going to be D, and Data would end up as C. This bugged me from a convention standpoint, so I aborted the install and rebooted Mac OS X. I went into Disk Utility, deleted the Data partition, and rebooted back into the Windows installer. This time, I saw only the C: drive assigned.

Upon all the files being copied over, the computer restarted. However, it booted into Mac OS X. I went to Preferences / Startup Disk, and to my relief saw the Windows drive was now an option. However, the system booted with a DISK ERROR on the Windows side.

Gah! What we basically need is to have (1) Bootcamp apply its magic partition handwaving, which means it has to be involved at some point to make the system changes while (2) sticking the Windows partition at the very end of the disk. The DATA partition will be in the middle. I tried various things of splitting the DOS partition, but BootCamp does strange things to the partition table. The workaround, however, is to not worry about the DOS side...make the MAC side big enough to contain both the data and itself, and after bootcamp is installed THEN you shrink the Mac partition and format the data partition!

Well, I tried it, and it doesn't work.

One difference I noticed in the instructions, on a more careful reading, is that the partition adjustment was done via the Leopard CD's Disk Utility; that is, booted from CD. That makes sense, as it's tough to work with an active partition that is also the startup disk, as magical as this new resizeVolume command is. The other thing that might be a problem is that if you change the partitioning on a disk, the reference numbers also change, and these are hard referenced in a file called Boot.INI on the disk. So, editing THAT may be necessary as well, but since the disk is NTFS, OS X can't touch it unless.

SO before I start this again, I'm going to use WinClone to back up the partition onto a USB drive I have. This is a shareware app for Mac OS. Incidentally, there's a very good description of what BootCamp does to the partitions on the WinClone site.

Ok, that didn't work...again. UNMOUNTABLE_BOOT_VOLUME error flickered briefly on a blue screen before the screen winked black.

I recall back in the late 90s, when I was moving from Windows 95 to Windows NT Workstation 4.0, of having some woes reconfiguring my system for dual boot between the two, and I had to edit the BOOT.INI, a hidden system file.

I noticed that the Startup Disk dialog for Mac OS X had something called "Direct Disk Mode", which turns your computer into a firewire drive. Heck, why not? I put the Mac into that mode, and then plugged it into my PC, which CAN. And this worked! I edited BOOT.INI manually, bumping up the partition number, and we are working. Whew.