KB, I think the OP is looking for a nice set of userland tools which was included in xServer
Pretty much.
Since we were about to purchase about 8 new xserve to build a new xSan on top of an active raid 16 1 tb disk enclosure as our new production environement, we are exploring other possibilities, open source (preferably) or not.
I took a quick look at redhat's GFS, and it seems promising and do pretty much what xSan can do. I'll dig more into this.
Regards,