Question is, what formats will Morphix derivatives read and mount persistent homes from? ext2, yes. FAT32, no. Others?

Background: Was messing around with persistent home on Gnoppix/Ubuntu live CDs (they're essentially the same now). They're both based on Morphix. Persistent home works when you create an ext2-formatted loopback file system ("morphix.img") on an ext2-formatted partition (which can be a USB key).

However, a loopback file system won't load from a FAT32-formatted USB key. (Nor will Gnoppix/Ubuntu use the entire USB key as persistent home, even if it's ext2-formatted; it seems to want a loopback image.)

One would assume it would also mount an image saved on an ext3-formatted partition...? How about plain ol' FAT?