An interesting twist for the SheevaPlug: use it as a testing tool for networks... http://www.wired.com/wiredenterprise/2012/03/pwnie/?intcid=story_ribbon

Here is the link to the modified SheevaPlug: http://www.pwnieexpress.com/eliteplug.html

One drawback: it's more expensive than the blank SheevaPlug.

Cheers, Peter