I have a plugged Anakee2, which held air just fine, that should have 1000 miles left in it by most people. More if I'm riding it.
I know that's not a new tire, but it exists.
O course, if you are coming to Austin you might as well check with Lone Star. They usually have at least a Tourance in stock for a GS
2009 BMW R1200GS Adventure