Wow. That's a really good question. Anyone put a hitch on the front end?
I just read that the TI has a minimum overhang of around 6' past the Hobie cradles, when they are separated 67".
I don't know what options exist for mounting the front hitchpost directly but I think you have the right approach. There are any number of bullbars/winch combos that could have a thule receiver inconspicuously welded on - if you research it and find a good shop to do it.
It still may be tricky to load the TI from the front, due to the gap, but transferring the hull forward and unloading from the front should be easier.
However, if the Airstream is going to sit for days at a time, I was thinking that you could still load/unload using a goalpost in the rear and then move the Thule to the front bar for longer transport w/ the trailer. Short of having a powered lift, that would be the perfect combination. You would need a way to attach the rear post, such as a suitable dual hitch adapter. It all depends on how your Airstream is setup, but it's something to consider.
Sounds like fun. If I really wanted the adventure of a lifetime, I would get the TI and find a way.