Eric, you have many options with ipe. If I were to go that length, I would my handle/fade section longer than normal and my tips stiff to minimize the working length and have the angle benefits of a longer bow. Ipe can handle it.
I would have 14-16" of nonworking handle/fade, and at least 7" of stiff tips. Like Mafort mentioned, make sure you don't have excess mass in the tips and you should have a good performing bow.