You're roughly my size, bigbossman (I'm 53 with a long-ish stem). I might know someone with something for your friend.

There's apparently quite a few rental spots (http://bicycleaustin.info/getaround/#rentals). I prefer Yellow Bike over all those shops (not the best LBSes IMO) but they might not have much more than gaspipe. Bicycle Sport Shop probably has the biggest selection (though University cycles won't be bad either). And of course, there's always Lance's Mellow Johnny shop.

I'll try to toss a thread up on this before the actual show so that we can organize any details then?