It's disappointing that i3 is constrained to one window. The ability to replace Microsoft's window manager with i3 and allow linux and windows apps to be nicely tiled together would be amazing.
Now, it ain't tiling, but I once worked (not as the first guy, but took it over as a major project and the hell out of it) was one of the ports of Opebox-ish Windows managers (to be more accurate, really an Explorer replacement shell, not a Windows manager traditionally) to Windows XP to build very stripped down Windows kiosk machines with minimal UI and a lot of control, custom UI, and cool fun features.
God I miss this. It was way ahead of the time and I guess Microsoft got their UI act together, then lost it, and are trying to find it again.
As for tiling, the best you can do are these:
https://github.com/fuhsjr00/bug.n
https://github.com/ZaneA/HackWM
The latter is by a budding Chicken Lisp; I found him and love a lot of what he does; not sure he is ready for prime-time.