should be relatively easy .. it will be a combination of the built in 'print skin' and the repository permalink.
If you are using a container that has the 'print' action enabled, you've seen this work, the module is opened in a new window with just the module contents, none of the headers, menus, etc.
The permalink token in the repository module allows you to display the module with only the 1 item showing.
Combining the 2 should allow you to open a new window with the contents of a single repository item for printing.
I haven't done this, but off the top of my head this is the approach I would take short of making a code change to provide built in item printing.
I will try and work up an example in the next day or two, but in the meantime, if someone else takes a shot and has any success, please share