RBC Business Avion. IIRC the bonus is usually 15k. Right now the offer is 20k. Also, something I hadn't noticed is that if you hold either the Plat Avion or infinite Avion, the annual fee on the business card drops to $50. So a 0.25c/Avion (or AA or Avios...pre any transfer bonus).
Not sure how tough they are on "business" definitions but I do have a business account at TD so could use that. I'll give it a shot and report back.