EvilInnocence has one for M3:

http://www.evilinnocence.com/index.php?widget=Store_Model_Product&id=379

There's also something in my runtime titled "Bernie's Rip Top" but I have no clue where I got it. Anyone else know this one?

Another option is to simply turn off a few body parts of the shirt. Depends on the model, but I often can turn of the shoulders or abdomen to make a perfectly nice long-sleeved shirt into a ragged mess. grin