There was a thread just not long ago about BBW/Busty MPA's. Just scroll down further in the Review board.
I can vouch for Alexia at AGS (recommended).
Pickering Angels also has some Chubby/BBW's. (best to do a walk-in to meet them in person. Pictures are not always accurate.)
It really depends on your own preference level or definition of BBW.
There was also mention of others, but I don't have first-hand experience with these:
- Zayna and Daisy at Muse.
- Alexis at HFH (previously Muse)
Maybe TOFTT and report back.