Hey fancsali, I have seen the situation of images, but no code before with the Nexus 7 deb.
I guess it would be best if you start from the porting guide: https://developer.ubuntu.com/en/phone/devices/porting-new-device/ . It should be somewhat easier to get anywhere since you're not starting from scratch completely, but the old canonical branches.
Chances are, the only way to answer the question about deal-breaker issues, is for you to try and find it out. Anyway, even if there is a deal-breaker, I'd say it is a contribution to learn how to build it, maybe get it into the ubports repository for others to build on in the future, or at least document it here. And who knows, maybe you can use the lessons learned some time on another device.
I'm at the same point with the deb, where there are some images around, but no code in the ubports repository (unless it has changed in the last months). It's on my list to try to build it myself but it keeps dropping to the bottom of my list 🙂 ... one of these days.
Good luck!