I think the paleo early adapters (mark et al) already will make the most amount of money in these older niches. You have to put your own spin on it to make money instead of following what's already out there.
What is something you can do that doesn't compete with the current leaders, but will instead add to their services? Something they will be willing to endorse on their websites?
Paleo is a very internet (grassroots)-driven enterprise so you need to be either be first on the (niche) market or you need to be better than anyone else at marketing your product (on the internet).