"RAID is not a backup" and that's the problem. Many people do not get their head around it.

Mark: The videos module does support storage groups too.

I do like the sound of this so I'm going to look into it further next time I rebuild my MythTV. Currently my recordings and videos are split up appropriately across a few drives with some strategic links to the separate file systems i.e. it doesn't share the space as efficiently but it's close enough for now.