Zfs root & boot

I did a little test with OpenSolaris and it seemed sluggish.
However, someone else may have liked it and that's why I need to say it was just what I saw on a 2GB C2D machine.

ZFS was very nice and that's why I'd like to try it out on FreeBSD.
However, I'd like to use it for my root partition.

Here are two articles on how to do that:

However, FreeBSD can't boot without the help of an UFS partition with a bootloader on it.

What would it need to be able to boot from ZFS? Does it still need that UFS partition in 7.1?

If it still does need it, I'd like to see what can be done and do what it takes to fix that and allow native ZFS boot.
may be to write a string in make.conf
echo LOADER_ZFS_SUPPORT=yes >>/etc/make.conf
cd /usr/src/sys/boot
	make cleandir; make cleandir
	make obj depend all install
No, I didn't forget.
I used gptboot, not gptzfsboot because there wasn't one :(.
How do I get the gptzfsboot file? I followed your guide to enable it with ENABLE_ZFS_SUPPORT=yes and it didn't work, I don't get a gptzfsboot in /boot or anywhere else.
from http://en.wikipedia.org/wiki/ZFS

When entire disks are added to a ZFS pool, ZFS automatically enables their write cache. This is not done when ZFS only manages discrete slices of the disk, since it doesn't know if other slices are managed by non-write-cache safe filesystems, like UFS.

It is relevant to FreeBSD ?

I ask this because I've only one disk in my laptop, but I'd like to test the performances of ZFS under heavy loads.