> If it were software RAID is it possible to boot from such a system?
> Does /boot not have to be a file-system which can be read by GRUB?
GRUB can boot from a software RAID-1. I often set it up so.
The difficulty is going to be in keeping the two s/w RAID systems apart.
I'd do that by partitioning the disks manually before applying any RAID
setup, then do each RAID entirely separately.
Windows has some strange (and apparently secret) rules about what it will
and will not do with different sorts of disk setups. You probably won't
hit any, but be prepared for pain if you do. parted and friends won't
touch anything but simple Windows partitions...
