You guys have done such a great job and I know ya got alot on your plates, but I figured I'd just throw in an idea for a new appliance.
How about an iSCSI server (iSCSI Target) appliance. This could either be a new appliance or build the feature into the FileServer appliance.
I found an open source project called, "LIO (linux-iscsi.org)" which looks great. I know very little about this project, other than reading thru their wiki site.