Insurance should cover it under your comprehensive/theft and vandalism coverage, unless your deductible is too high to warrant filing a claim (for all intents and purposes the AP is basically a "PDA"
). If your car insurance won't cover it (or isn't worth it), try filing under your homeowners or renters policy. Mine covers my belongings that are stolen out of my car or anyone else's.
I can't imagine this has never happened before. Several months ago I foolishly left my car unlocked overnight accidentally and some punk kids in the neighborhood stole my iPod. My AccessPort was just inches away in a little hidden compartment/cell phone holder I have installed in the door of my center armrest. Thankfully it wasn't seen, but after that I started keeping my AP in the house. Hindsight is 20/20, though. Sorry for your loss and I hope the good folks at Cobb will be able to help you out.