A possible solution might be, since they are selling the application and not providing a service, is for users of the software to create their own application tokens and putting them into a new settings panel. There's no loss in sales, it does require an extra couple of steps for a user to get going but putting something like this in the advanced section or releasing it with just the Alpha might be very good solution.
I imagine Twitter's reaction to a major client doing such a thing would be less than favorable to developers (no more free API keys, if I had to guess)
