Equallogic's architecture is pretty sweet in terms of ease of use and performance (with multiple arrays at any rate) but it chews up raw capacity fairly aggressively. If you want to make full use of hardware snapshots for example just following Equallogic's recommended reserve numbers 4TB of raw capacity becomes about 1.8GB (RAID 5) or 750G (RAID 10) and my experience of them is that you ignore those recommendations at your peril.
Cost wise the PS6000's aren't exactly cheap but the new "entry level" PS4000's seem to be a nice trade off (much lower cost, half the bandwidth). The $30k you mention was almost certainly for one of the PS6000 range, I'd go back and ask about the PS4000 as it should be a lot less than any Clariion solution with a similar capacity.
One major issue with iSCSI and VMware ESX 3.5 (and earlier) is that the VMware iSCSI software initiator (if you are using it) is pretty weak - doesn't support TOE\iSCSI offload, is a single threaded stack with meagre multi-path capability so there's no way to get Native ESX iSCSI to utilise more than 2Gbps of bandwitdh. iSCSI HBA's can help a bit but the best solution is to move to ESX 4 ASAP - the new iSCSI initiator is substantially better and the revised pluggable storage architecture supports proper dynamic multipathing for iSCSI. This will mean substantial performance and scaleout improvements for Equallogic (for those environments that need lots of bandwith\IOPS).
Expanding these in the future is extremely simple too and their AutoSnapshot Manager / VMware Edition can do some pretty neat stuff in terms of replication although you will need multiple arrays to get the most out of it. One important thing to remember about Equallogic is that all of the software features (including the MPIO drivers and ASM) are "free" - this is not true for EMC kit and those costs add up very fast.
One other solution to consider might be something like LeftHand's Virtual SAN Appliance. I think it costs around $3K for up to 2TB of shared storage - it basically allows you to use the local storage on your ESX hosts as a virtual SAN. I can't comment on performance or scalability but the concept is pretty neat.