Thing with Tron and GR, for one, is they're fictional bikes, no licenese to pay for a brand name and design. Another thing is the design, the Tron bike is pretty simple in details and the GR Bike is very organic and pretty much a solid mass. A Fatboy would have a pretty intricate construction. I think between the licensing and work, they'll probably opt out of it, though it would be awesome if they did because the bike I have is too big.
I'm hoping the BD is coming and just held up to save 1 figure for the 20th Anniversary of the movie.