A mishmash of the afro, fedora, rubber glove hats, with a beard tacked on.
This is the clientside replacement version of the combihat. Grab the serverside one from here: http://www.mantaengie.com/2009/09/06/i-have-no-idea-what-to-call-this/
Simply extract this into your tf/ base folder, it should replace all three spy hats with the combihat. If you don't want all of your hats being replaced, delete the offending sets of files and they should revert to normal. The hat file sets are: spy_hat, derby_hat and spy_camera_beard.
Delete all the files that were extracted into the models\player\items\spy directory.
There is no materials folder, the hat nicely uses both team materials off the original hat models.