Tourist Trophy - Motorbike game from the makers of GT4

Let's say you're Polyphony Digital. You're coming off the great reviews and impressive sales of Gran Turismo 4, and every Gran Turismo game you have made has been an improvement on your previous work. You're basically considered the greatest development house for racing games and one of the jewels in Sony's crown. You have unrivaled access to the newest cars and the best tracks in the world. When it comes to simulation racing games, you're king. If a gamer is serious about cars, he has a PS2 and at least one of your games.

What's next? The obvious answer is a Gran Turismo game for the PS3, and I have no doubt they're cranking away at that right now. There's also the PSP port of Gran Turismo 4 which is starting to look more and more like vaporware. Aside from that, what do you do? Where do you go?

Motorcycles.