Hi, I've been looking at ostree recently, with the intention of using it in conjunction with xdg-app. David King and Alexander Larsson have made some Ubuntu PPA packages, which don't necessarily have all the integration that you had in mind, but they have the advantage of already existing. Even if they can only deploy non-Debian distributions, that's a good start.
Would you mind if I tidy up those packages and get them into experimental? Would you like to be a co-maintainer? I had been intending to put them under the pkg-utopia umbrella, but collab-maint might be more appropriate if people outside that team are interested. Regards, S