OK, I am successfully running b13 with the patched kernel linked above and ext3'd drives. There was only one minor glitch in the upgrade. I assumed that the stock empeg kernel would simply mount the drives as ext2. Instead it complained about "couldn't mount because of unsupported optional features" and did not mount the ext3 drives at all. After upgrading the kernel everything works fine.

So if anybody does change to ext3 and then wants to go back to ext2 you will need to delete the journal file and do an fsck to get the bits cleared so that the stock empeg kernel will mount your drives again.

-Mike