Synology offers iSCSI on the cheap
While the Promise/DataCore combination offers an excellent feature set at a relatively low price, how about an 8TB RAID5 iSCSI system for $2,500? Synology makes the DS509+, a storage device intended as a small-to-midsize business (SMB) network-attached storage (NAS) system, but it supports iSCSI as well, and costs about $870 at Amazon.com.
The five-bay device comes without drives, so five 2TB RAID edition drives would be another $1,600 or so. The DS509+ doesn't provide replication, mirroring, snapshots or cloning of volumes, but what do you expect for this kind of price?
You could add all the features for another $2,000 of DataCore software. Though you won't get the performance of a system like the EqualLogic, it was still usable for basic server storage. It also offers a nice NAS server compatible with Windows, Mac and Linux, as well as a wide array of SMB-oriented features, such as backups for PCs and laptops, a Web server, database server, a media server that can stream to PCs or iPods, and even an external sound port so you can have music in the server room (or pipe it into the phone system).