Lately anonymous suggested on the blog that you make a feature for designing your own Grand Prix. I know you can go into the data but for some users that's too messy and too difficult (I don't see why, it's only copying, pasting and checking).
For an idea. You select "Create Your Own Grand Prix" and it will swipe the grand prix region clean. The grand prix area is now just a text area where you type the name. Next the grand prix icon appears with the STK logo. Now in the tracks area you may click on each track. It will come up with the normal select with the laps and the button "Add". Once you are done simply click "Finish". And then "Play".
Sorry... just -- thinking of something.