When I discovered mine expired (in Sri Lanka of all places...), I prepared a simple document authorizing a family member to receive a new one from the local Automobile Association. I emailed the document to my proxy along with a scan of my driver's license. He printed it out, went there, showed them the document (which was not verifiable AT ALL), and got the IDP within minutes. He scanned it and emailed it to me, and I printed it in high quality on a cardboard-type paper at a local Internet Cafe. He then express-shipped it to me. It took a week to arrive, in which time I was stopped a bunch of times (policemen stopping nice looking cars looking for a quick bribe is very common in Sri Lanka) and showed my version of the IDP. No one was able to detect an issue with it.
Not sure how US IDPs look, but where I'm from, it's a simple folded cardboard printout. My high quality printout was basically indistinguishable from the real thing.
I don't know about the legality of this interim solution, but I do know that it worked quite well. Since you actually do get a new IDP using this method, the serial number on it is valid and corresponds to your identity (hopefully it would never get to a point where this needs to be checked by anyone, but hey...).