I think there are tons of niche ideas that are still capable of being capitalized on. For instance, things for Hawaii. For most people who reside in the continental USA, they still think we live in grass shacks and wear coconuts and grass skirts to cover up.
I tried to join www.thegrocerygame.com but realized that there was only one store for the island of Hawaii. I guess due to the fact that Star Market and probably at least one more is locally owned, they don’t have the resources to go through and list all the sales. This is where Hawaii residents come in. I would love to do it but it would take an insane amount of effort, something of which I cannot give at this time. But this is just one major idea. There are TONS more specifically for Hawaii. If you can think of one, let me know in the comments.