I don't recall any previous posts about this particular window problem. Nor has anyone contacted me off-Forum with a question like that.
I will tell you something that you probably already know - the windows in our T1Ns went out of production some years ago due to companies being bought and sold and folding and other various and sundry corporate machinations (somewhere in my notes I have the entire chain of events written up). As a result of this, there is no dusty corner of a warehouse with compatible spare windows or window parts sitting around waiting for a T1N Interstate owner to order them. If we have window problems, in many scenarios we may be forced to consider ourselves SOL (sadly out of luck). Either that or put a lot of effort into a DIY solution to our problem.
It was partly for this reason that I'd hoped to figure out how to identify any junked T1N Interstates that were in the process of being sold for parts anywhere in America. That possibility came up about a year ago because many of us are missing the trim piece off the sliding door window, and another owner had asked what the heck he could do to replace his. Curious myself, I launched a search to see if I could identify a means of locating either junked Interstates or junked non-Interstate T1N Sprinters that had the same brand and model of window installed, because Airstream wasn't the only buyer of that product. I'm sure such vehicles are out there somewhere, but I did not discover a means by which I could track them down.
Wish I could be of more help at this point. Can you post a pic of the window?