Trying to run ChromeOS on an Asus eeePC 900 but failing.

I'm trying to boot an old eeePC 900 into ChromeOS from a USB thumb drive and I'm hitting a brick wall which is leading to a certain amount of yak-shaving. I don't really see why this should be a problem because there are plenty of Linux distros that manage this easily and just work. Like SystemRescue for instance.

So here's the deal.
- Download a recent ChromeOS image from http://chromium.arnoldthebat.co.uk/index.php?dir=weekly%2F
- Unpack it, and copy it onto a 4Gb USB drive using Win32DiskImager.exe
- Plug it into the eeePC and boot. Hit Esc on the BIOS screen, choose the USB drive
- Fail with 10 or so lines about a Kernel Panic.
- Google for ChromeOS Kernel Panic and find out that ChromeOS hard codes it's location as /dev/sdb But of course an external USB on this machine is going to be /dev/sdc
- Discover you can over-ride this by hitting esc during the ChromeOS boot and typing chromeos-usb.A root=/dev/sdc3 to tell it where the boot partition is.
- Get past the kernel panic but now it says "Your system is repairing itself, please with" then reboots.
- More googling suggests this is due to a missing or corrupt STATE partition, 1Gb on /dev/sdc1 There's a suggestion to look for unencrypted/clobber.log on the STATE partition to see how it failed
- Fire up SystemRescueCD. Fix /boot/syslinux/syslinux.cfg so ChromeOS boots from sdc. Try booting again. Goes into the repairing cycle again.
- Discover that the STATE partition should be EXT4 but is displayed as UNKNOWN by gparted, realize my old copy of Systemrescue doesn't support EXT4, re-create my rescue thumb drive.
- Start again from scratch
- Check the ChromeOS drive before trying it out. Fix the boot target. Check that STATE looks ok, is in EXT4, has a directory structure and stuff.
- Try and boot. And guess what, it fails with "Your system is repairing itself"
- Go back and check it again with SystemRescue and discover that STATE is now back to "Unknown" file system

So:-
1) ChromeOS can't cope with booting from a USB drive if it's not /dev/sdb Excuse me, but WTF?
2) It's getting confused by the STATE partition and then failing completely to sort it out, actually making it worse.

So now what?

It's just a Linux distro with most of the UI being through a copy of Chrome, right? How hard can this be? Why doesn't it "just work"?

Can anyone here help with this?

BTW. I've put this into discussion, because there's no obvious category to place posts about running ChromeOS on non-chromebook hardware. Doing a quick search here, there are a few other posts about this and similar problems from people trying to do similar things.