A few possible gotchas regarding fdisk and disklabels. DragonFly has a 64 bit disklabel feature now (disklabel64), as well as gpt support, but lacks boot support for either.
I think the fdisk utility needs to be separate from the disklabel utility. Also as HAMMER moves more into the mainstream the recommended partitioning scheme is to only have two partitions... a small UFS /boot, and everything else in a single HAMMER root. -Matt