And re: Thunderbolt, well while it's fast, it's just a bus. You still have the cost of adapting it for a particular purpose. The cost of integrated adaptation, inside a storage enclosure for example, doesn't seem that unreasonable to me. But Thunderbolt to FC for minis is $800. And if you want 10GigE, I'm not even sure there is such a thing yet, although OWC has a ~$400 PCIe enclosure, and you can put a 10GigE card in that.
For enterprise storage, Mac OS relaly isn't the platform: Not from the hardware perspective. And not from an operating system perspective [1]. And not the file system either, JHFS+/X just don't count anymore than NTFS does. There's way way more interesting stuff happening elsewhere.
[1] Windows= 5 years features updates, 10 years bug/security updates. Red Hat Enterprise Linux (or CentOS) 10 years standard, up to 3 additional years extended support for RHEL. Mac OS X is in the realm of 2-3 years, and in fact it appears anyone who wanted to upgrade servers to Lion, can't now. It barely gets stable enough before it's yanked from the App Store in favor of the latest version.