i think bridge vlan filtering is ready to land... if anyone is interested in reviewing it, the top of the review stack is here: https://reviews.freebsd.org/D50577
there's some more cleanup/improvements to be done, but i really want to get this in so people can start testing it.
(tl;dr, this lets you have a single bridge(4) to handle all your vlans, instead of having to mix-n-match bridge(4) and vlan(4) which is ugly and complicated.)