I think Cordia is dead, mostly due to a lack of interest from other people.
Could be wrong though, in which case, someone please correct me.

Either way, what's the use of running the Hildon UI on Sailfish OS when Sailfish OS itself is mostly just a UI running on top of Mer, a fork of Meego, the successor to Maemo, a fork of Debian?
Why not just run Hildon UI on Debian or Mer itself?

And I haven't been tracking this a lot due to a lack of interest, but I think the Jolla device is still locked up with no sources released yet.
Again, correct me if I'm wrong.

Anyhow, here's something to keep in mind: requesting something is easy.
You spent the time, sitting at a desktop, coding and debugging for hours on end, fully aware that you're serving a niche and that you'll be stuck giving out tech support for the handful of apps that support the UI/framework that you spent lots of time on developing.

I think the closest you're gonna get to Hildon, is by hacking away at an existing window manager first or perhaps even creating an entirely new one for your average run-of-the-mill Debian-based distribution.
Heck, just join the "Fremantle Wheezy" team, if that's still a thing.