Sounds like a plan ;)
FWIW, there were an attempt to port OpenStack to FreeBSD by Semihalf few years ago: https://github.com/Semihalf/openstack-nova. This wasn’t merged upstream though; this was bhyve-based.
I’ve also had OpenStack running on FreeBSD, using Xen though: http://empt1e.blogspot.ru/2015/06/openstack-on-freebsdxen-proof-of-concept.html. I didn’t manage to upstream any of this though.
If you’re planning to upstream anything, I’d suggest to start as early as possible, because probably there are some bits that would require refactoring (i.e. bits that are written with Linux in assumption where in fact needs to have interface/implementation with Linux/FreeBSD drivers). Also, CI might be important here too…
Anyway, please let me know if you need any help.