I don't really get that part. You have everything needed to build it yourself (and so host it) on the wiki [0].
Also, everytime someone builds something now, it seems to be the first comment out there "it needs to be self-hosted". I get that this is a security oriented communication app, so it needs to be audited and open sourced so we can trust it, but now that this part is OK, people are finding something more to ask: the self-hosting part.
I had the X1 carbon 3rd gen and I have the XPS 13 9350 right now, I don't see a lot of differences in the keyboard. Why do you like the ThinkPad one better?
It's sad to see you had trouble. With the latest version of it (9350), I had trouble at the beginning but upgrading the kernel to 4.4 solved all of them.
Also, regarding #3, I've heard Linux Mint as great HiDPI support in their last version.
"Providing machines for Kubernetes in not only necessary as a pool of raw cycles and bytes but also can provide a critical extra layer of security". [0]
Maybe it's true for now, but containers may be enough security in the future.