So they aren't ready, don't want us to have them, but want to sell them to us still via the Microsoft store?
So to narrow the scope since I was typing quickly as I heard the information.
Microsoft Device Night
1. Microsoft Lumia 950's are present there was at least 12 present at the event.
2. A question was asked by an attendee asking about the availability of the 950XL and why they weren't present.
3. The response/answer was that the software was glitchy and the didn't want to bring them, hence the reason why they wasn't present at the event.
4. A question was asked availability of the 950XL and support from other carriers.
5. The response was that they are still working with Sprint/T-Mobile. He said that the 950XL (when available) will be sold in the Microsoft store only as it's more of an international phone.
6. The question was asked about when the phones will back back in stores to play with/ have a demo unit.
7. The response was that for the 950XL they won't be in the stores until the day of release.
SideNote: This is a guy at a Microsoft Device Night event and is probably not a high up employee like Satya and them.
In response to #5, in my opinion it sounds like nobody is picking up the 950XL as far as carriers hence the reason why he said only Microsoft stores will be selling them. It looks like an international only device which will be sold here only in Microsoft stores due to them carrying everything and they will be sold unlocked to work on most carriers (maybe minus Verizon?)
This also probably explain the reason why we have only heard the 950 having a release date from AT&T and not the XL model.
Hopefully, this clarifies anything with a little of my opinion at the bottom.