Tom's Hardware just ran an article about the Half a million dollar Petarack, from Aberdeen - a storage appliance providing One petabyte of storage in a single rack.
It runs a variant of OpenSolaris, and ZFS. And strongly advocates against hardware raid, and unlike the Pod approach uses enterprise SAS drives.
Looks Sweet - I think I have my next DIY project.....
What Does One Petabyte Of Storage (And $500K) Look Like?
Though I do think the product name could be better, it sounds like a device for torturing folks who harm small children.