I wanted to report that I succeeded in using iSCSI (on an Openfiler server) with Time Machine via a gigabit link with jumbo frames (MTU of 9000) enabled. The secret to my success? I used the iSCSI initiator from http://www.small-tree.com/. It appears as if the iSCSI initiator from globalSAN is just a plain broke down piece of shit. Well, you do get what you pay for. Hurray for me and my buddy Steve over at Small Tree!