Most SAN administrators wouldn't be caught dead using your $130 1TB drives. Rerunning your calculations with 15K 450GB SAS drives (around $300 bucks), and you're spending quite a bit more: 228 drives will give you 100TB, sure, but we'd want some redundancy . . . say RAID 5 (not the best approach for SAN design, but let's keep it simple) which pushes the drive count up to 304 with a total cost of $91,200, just for disks. To get a real, enterprise enclosure (or rather, cluster of enclosures considering the drive count) that offers things like FiberChannel, 10Gb iSCSI, or InfiniBand uplinks, and features such as SAN to SAN replication, bit deduplification, and other enterprise-level utilities/features, I'd say you're looking at $500,000 (ballpark guess) just to have something to stick the drives into. We're at ~$600,000 without even taking into account the physical costs of operation, datacenter architecture, or labor costs to maintain such a SAN.
Suddenly, that $1 million isn't so far fetched, eh?