Xserve and CX3-20

i am afraid not ...i just ran a report in E-Lab and even thought they have a few LSI HBAs (that's what apple uses and calls them Aplle hba), fibre channel/iSCSI connectivity is not supported.

I am sure Apple would love to sell you some proprietary storage for that!

you bet ..it's going to be called iStorage ..and everything is going to be snow white color. Seexxxxyyyy

There actually is a solution for xSevers and EMC, but it's only available from EMC's group that deals with the video/motion picture vertical market. From that group, there is a solution with ATTO cards, a custom PowerPath driver from ATTO, and the CX3. Problem is, they don't seem to want to sell the card/driver separate, or to customers outside that particular market.

Here is the particular white paper I found concerning the solution.
http://www.attotech.com/pdfs/TechBrief_EMC.pdf