Agree with everyone on here who says that USUALLY, if we do the work for them, then they are okay with you (or whoever oversees FA) putting together a PD for them. I say usually because some are worried they wont be "getting their moneys worth" out of Marzano or whatever other speaker they paid way too much for.
In some of the different districts I have worked, we have:
1. Traveled to a school in another district who had school that day and observed their methods.
2. Brought in someone retired to help out with vertical alignment
3. Brought in nearby college professors to give us a brush up on something like double reeds
4. Once we had a REGION provide PD sessions for any band director in the region who was able to attend.

Most of the time if you lay it out in a presentable way (not just telling them you are going to talk shop) then you are good. Good luck