Creating a system RAID-10 device

[Sven Willenberger]

I hope this is the appropriate mailing list for this question, if not
please redirect me as needed.

My goal is to create a filesystem consisting of a striped raid array
over 3 mirror raid arrays that would encompass the entire filesystem
including the /boot and root partitions.

Generally I would create a RAID10 from 6 disks as follows:

gmirror label -v -b round-robin md1 da0 da1
gmirror label -v -b round-robin md2 da2 da3
gmirror label -v -b round-robin md3 da4 da5

gstripe label -v -s 131072
md0 /dev/mirror/md1 /dev/mirror/md2 /dev/mirror/md3

newfs /dev/stripe/md0

naturally the problem here is that it cannot be done on a system that
booted from da0. I have seen the example of setting up a mirrored system
drive
(http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/geom-mirror.html )

which won't quite work for my case either. Using this method I could
probably get the one mirror (md1) to work, but I know of no way of then
adding the other 2 mirror sets and then redoing the system to stripe
across all 3 mirrored sets.

The only thing I could think of was to boot from the livecd and create
the 6-disk array and then trying to install FreeBSD onto this
filesystem. In order to do this the installer would have to
recognize /dev/stripe/md0 as a valid "drive" -- is there any way to have
this happen?

Sven