First, it sounds like a great idea you have going!! Some of the things that I would consider if I ever boarded my dogs are:
1. large dogs vs. small dogs. I actually think that some segregation is important. My small dogs love all animals, but when a big dog comes up to them, they get scared. It's not even the presence of the larger animal, it's the bark. We have neighbors with large dogs and when they bark at night, mine run for cover.
2. (and I"m sure you thought of this) verification of vaccines, including Kennel cough. This is one of the major reasons, I don't think I will ever board my little dogs. I don't think there is enough checking to make sure that all the dogs are well vaccinated.
3. having two dogs myself, I particularly would look for a two dog discount or the option to put my two little ones in the same suite.
Just a few things...hope this helps and I wish you the best of luck! I think it's great that you are taking what you love and trying to incorporate it with what you do for a living!!