I hope this works out for you also.
I would love to open a store myself, but I am only able to buy things, and never part with them. Heck I have never even offered anything for sale on these boards before.
old trade in are a must, If not for the amount of turn over cash just think you could start destroying games just to make the ones in your personal collection more rare.
Please if it do come to be, DO NOT throw all your lose carts in a bin like they used to at EB (etc.) It used to make me cry when I would see little kids throwing them all around to find what there looking for.
Snack bar seems cool but food and drinks usually don't mix well with electronic equiptment, and you would have to deal with public health board and such.
Best of luck to ya.