Sun Microsystems has announced their new storage line, which they call "Sun Storage 7000 Unified Storage Systems". These systems are based on x64 architectures (AMD dual or quad-core), 1 Tb SATA disks, SSD add-ons for caching and of course ZFS.
The high-end system - the 7410 - supports a maximum of 288 Tb (raw), requires 48 rack units and about 7.5kW at max load.
With the "clustering" option, a second system can be connected in order to provide redundancy and an additional 288 Tb. So what you'd get would be a NetApp-like configuration with dual controllers and a total of 576 Tb.
According to the Sun website, this clustered configuration's list price would be close to a million dollars, which translates into $1750 per raw terabyte. Although this still isn't a true cluster (in an Isilon way), ZFS *is* very cool and with a nice discount, this could be worth a look...