If think, on FAS6000 (except 6210 & 6040) ... if you have 64-bit aggr then the max limit is 100TB. Including snap reserve and disk overhead space. Not that you can't, but just curious to know, why would you setup such a huge LUN (that to iSCSI) for production environment? Unless this will be provisioned as QA or Dev or something else.
Keep in mind that for ESXi 5 the max. datastore size is 64TB but the max. VMDK size is still 2TB so if you would like to have a volume inside of your VM you will not be able to go over this limit unless you create an iSCSI LUN outside of the VM and use either RDM or MS iSCSI inside of the VM to connect to it.