Hey Josh,
I'm not sure if this is quite what you're looking for, but you can save a plot object associated with the FRB to disk using the ytdata frontend and then reaload it as a dataset. From there you could use yt's native profiling capabilities:
Unfortunately no one has added the ability to do 2D radial profiles to yt without this intermediate saving and reloading step. I still think that would be a worthwhile project with high payoff. Technically I don't think the FRB is necessary, one could do it using a projection or slice data object.
-Nathan