I know this is kind of random, and I have no clue if it works, my dad says it did before, but I think he was standing to close to the car.
Anyways, for those that remeber Jeremy and the Aston Martin that he put his keys to his head and he got more distance, this is similar.. except far more.. distance?
Get someone's keys with remote entry, and call their cell phone (through your cell phone), and somehow according to my dad (whom I don't believe), the infrared signal might be sent through the phones and the car will unlock.
I don't know if it will work on all remote entries, but it should be something interesting to test out, and even more interesting if it works :S
Oh, @ajp, well.. it's the only way!
Plus, consider yourself lucky if you do find a locksmith that will just go ahead and do it, and do it especially for under $100, it's expensive, dangerous, and few people have the tool to do it really.