I would really to to see as many of the Ironman bike courses on Zwift as possible. I know this could be a big undertaking, but I believe that those people committing to these races - that often are far away from where they live and train- would be open to an in app purchase sort of model for individual courses.
I think this presents a great opportunity to build a mutually beneficial partnership with Ironman (WTC) and build the Zwift user base. GPS coordinate files for most courses are available on line, and as long as the general features of the course and major landmarks are there, most would be super happy.