thanks for your twelve cents, Jack!
As a matter of fact, my first choice for Ellery was Keith Carradine. He wasn't 100% my vision of him, but he was the closest I could find - tall and gangly, long dark hair... missing only the slate-grey eyes (which Hugh Jackman doesn't have either.) Keith was close, in my mind. When DeeDee (from Bettermost) offered Hugh Jackman as a better alternative to cast as Ellery, I thought to myself (as did many other readers) : ah HA! So I was well into the third book (where you are, approximately) before a front-runner for casting Ellery actually emerged.
Keeping that in mind, however - casting of an actual actor is not really up to me. It is whatever works in the mind of the reader(s).
Always good to get some first-hand knowledge of the area to help fill out our mutual obsession with all things BBM!