Last I heard, no you can't use a DOS extended partition in a ZFS pool--it has to be one of the (up to) 4 primary partitions, /dev/dsk/c0d0p1-p4 using your Fdisk output. Or you can have the OpenSolaris install program format the whole disk.
By the way, I create a /usr/local ZFS filesystem that's not touched during OpenSolaris upgrades. Same with the /export/home. During OpenSolaris upgrade, Package Manager creates a new root filesystem that you reboot to. You can go back to the previous root filesystem using the GRUB menu or using beadm(1M). -- This message posted from opensolaris.org
