Well, I finally did it this morning.
Net::AIM. Net::Telnet. A little glue.
Bam. With perl, all things are possible. And most things are trivial.
The AIM username is MidgardMOO. When the proxy is running (it's not at the moment), you can tell it 'connect <name> <password>' and it'll open a mooltiplexor connection to the moo. From then, type commands as normal and they'll be passed to the moo, and whatever the moo sends you will be sent to your IM window. There can frequently be long delays if you're getting sent a lot of text, since my backoff code is Wrong. 'quit' will disconnect you from the mooltiplexor.
I won't even begin to go into the security implications. *shudder*