I've tried to flash my C3k with gpe-image-spitz-20051021200253.rootfs.tar.gz, and it does boot and start nicely.
I'm unable to suspend or switch off the Zaurus, though, the on/off button doesn't work, and issuing a "apm -s" command in the terminal result only in an error message (device busy or something like that, can't recall exactly, and I've reflashed Opie since...)
Did anyone else try GPE on a C3000 recently? It looks good, and promising, but if I can't turn it off it's a no go for me...