I don't think it'll work. You'd have no way to get the driver to run so you wouldn't be able to load the software RAID. I'm not certain you'd be able to install Windows 7 onto a Windows software raid either. Then again, I've only tried it on SATA raid.
Remember, any RAID related functionality of the Little Big Disk is provided entirely in software outside the unit.
Exactly, so why not eliminate the RAID business completely? Use the two disks in the external drives as just that? I am curious because Lacie says you can use their drives as JBOD without RAID. All the googling isn't coming up with anyone having done that, yet.