Also maybe it would be more interesting to join an already existing shop? I know of several guild owned stores and I'm very certain that practically all of those stores aren't open (read: shopkeepers online) nearly as much as they could be.
I do understand that it's always more attractive to start something on your own and be in charge but with that lies one of the main problems of our current player community. Too many people start their own projects, enterprises, guilds, etc. This divides our community in a whole lot of different and often very similar sections. A lot of those are great ideas but they die out because everyone prefers to try things on their own instead of joining someone else .. so most of those die out after a short while since there is no help.
Keeping a business running within a 24 hour online game is an intensive job. You obviously know this since you're already asking help ... trust me though, there are a lot of shops that are already worked out in great detail which could use that help just as much as you can.
I'm not trying to break your idea down or anything .. just a general remark towards everyone, our community and especially our economy would work a whole lot better if not everyone was so deathly afraid of working with/for someone.