There are industrial shredders that WILL shred anything.  There is a company, that frequently shows up on Discovery channel, that makes all sizes of industrial shredders.   They go as big as one that shreds cars down to shredding trash which includes 2x4s and cans.
 
http://www.ssiworld.com/watch/watch-en.htm
http://www.ssiworld.com/watch/hard_drives.htm
 

Brian Kelsay

From: [email protected] [mailto:[email protected]] On Behalf Of Sean Crago
Sent: Tuesday, September 30, 2008 12:18 PM
To: KCLUG
Subject: Shredder?

>I can't figure out why the government just doesn't remove the hard drives
>and send them to a shredder.  Even a private individual can achieve roughly
>the same level of security with a drill and a 1/2" drill bit. With the price
>of drives being what they are now it can't impact very much the resale value
>of the computer to sell it without a drive installed.

Shredders don't like metal, but there are things that'll make quick work of a drive:
http://www.networkworld.com/news/2006/062706-guard-dog.html

The Air Force seemed to think a 1-2 punch was in order, according to Cryptome: "2.5. Destruction. It is a good practice to sanitize media before submitting it for destruction. Media may generally be destroyed by one of the following methods (see Table 2.1). (NOTE: Although approved methods, options d and e use acid, which is dangerous and excessive, to remove recording surfaces. Options a, b, and c are recommended over d and e.) "
http://cryptome.quintessenz.at/mirror/afssi5020.htm

-Sean