OK, got it booting.

First: it was a disappointment. Not really any noticeable speed difference, and difficult to use because your entire system is running over a wiggly little USB cable connected to the HD. Perhaps an advantage to this is being able to load your system up with huge apps. But who does that anyway? If you really needs lots of system space, just get a 16GB flash card instead. Perhaps another advantage is being able to boot any computer from a single drive; you can install boot partitions for linux, Mac, Windows, NIT etc.... Hmm, still dubious.

After I've said all that, here's what I did (thanks fanoush, Benson et al!) to get it working. This of course assumes that you've got multiboot, and you've got an external usb storage device that mounts as "sda" on the tablet (you can determine this by looking at /media/usb when you plug in the device). This device could be a USB key or a flash card inserted in a supported flash reader instead of an HD, of course.

1. Use a partitioning app to create a second partition on your HD, formatted as ext2 or ext3 (I used ext3, so the howto assumes this). I used Debian QTParted to shrink my fat32 partition and create a new ext3 partition. It is just not a good idea to make the first partition of any removable device into a linux partition. Windows computers will have difficulty mounting it, and the tablet will do weird things, too, if you boot to it.



2. I cloned my OS2008 to my new partition. First I mounted my my new HD partition as /opt. As root:
(note that one or more of the first three commands may fail with "file exists", that's OK)

...and then I used Milhouse's nupgrade.sh script (steps 2-4) to do the cloning.

3. I edited my initfs_flasher/bootmenu.conf file to have the following entry:
4. I added the following to the very end of my initfs_flasher/bootmenu.sh file:

5a. I started the initfs_flash script to set up the bootmenu. I worked my way through the script, answering yes or no, until the "dropbear ssh" question. I stopped here and ...

5b. ...I opened a second terminal window. I gained root in the second terminal and, in the directory above the initfs_flasher dir (in my case, this is /root), I made sure that the drive was plugged in and working and then issued the following commands:

5c. I then went back to the initfs_flash screen and finished the flashing process.

DONE.

When the system reboots, your tablet should be able to boot to partition 2 on the external usb storage device.

So, fanoush, any possibility of adding some stuff to your initfs_flasher package to eliminate the need to do those hacks?