Just curious--is this a DC thing, or is it catching on in other cities as well?
A couple of places here have started making 32-inch diameter pies and selling slices. A slice goes for about $4. They have tried selling the entire pie, but custom-made boxes aren't working and it wouldn't fit in many cars. They sell a few jumbo slices at lunch and dinner, but mainly make their mark as a "nightcap" food. A single jumbo has over a thousand calories and almost fifty grams of fat. We won't even talk about the carbs.
Here's a link to the Washington City Paper's cover story on the origin and evolution of DC's jumbo slice, if you are interested: