How about an ioSafe Solo?
Fireproof up to 1500 degrees Fahrenheit for 30 mins
Waterproof in up to 10 feet of water for 3 days.
And not really much more expensive than a regular drive. (500GB goes for $149)

sorry I had to. It's just too cool.
Disaster Proof Hard Drives, External USB Devices and Network Attached Storage (NAS) that is Fireproof and Waterproof
Well, either you found something that I didn't or they have a little truth in advertising problem, because here is the cost on the order page for the external 500 gig device pictured on the link you posted. That is for one device with shipping to my location. $249.98 is a lot higher than $149.00
Subtotal: $249.98
Shipping: $15.91
CA Sales Tax: $0.00
Total: $265.89
The Whooping 80gig internal device was $199.99.
Here is a link to the purchase page with the prices for the different drives.
https://iosafe.com/rugged_usb/500GB-solo-external-hard-drive
As a barbaric killer of poor defenseless animals ( Yes I hunt) my gun safe provides me 3 hours of protection at 2,500 degrees F. as well as being airtight/waterproof and humidity controlled. One backup drive is always stored in the safe.