All the restaurant-related startups and announcements lately are an almost-daily reminder for me that when you have a good idea, jump on it. Ah well. I didn't have the contacts to pull it off, and it was only half an idea. :)
If you ask me, screw the grilled cheese restaurant. A grilled cheese van would be a licence to print money, second only to a cupcake van.
In fact, Orlando FL has quite a few food vans that occasionally all park in the same area for a mini food fair and attract a lot of people. They've become quite popular in the last year or 2. (I'm sure it happens other places, but Orlando is what I know.)