fathom - 7:31 am on Dec 22, 2012 (gmt 0)
The disavow tool simply forces a nofollow on the links cited in your list... that you have deemed as unnatural or inorganic.
PENGUIN simply does that as well... forces a nofollow on links Googlebot deems as unnatural or inorganic.
Google disseminating information based on TRUE FAQ does not suggest you should use, or need to use, or you MUST use the disavow tool to revert a PENGUIN issue... they leave that up to you to decide... don't put words in their mouth though... Google has never EVER implied the tool will do anything for PENGUIN problems.
So ... the disavow tool is 100% worthless for a PENGUIN issue... FULL STOP!