Good luck if you proceed with the venture. As a builder, and bike maintainer, I like shops that carry a good range of quality (but not flashy) wheel rims, tyres, brake parts, lights, carriers/bags, gears, and tools - ideally Park tools. Supporting home builders and maintainers is good for reputation, and for parts sales. The market for parts nowadays is very competitive due to on-line sales, but I'll pay a little extra to be able to see the part, and to be able to return it easily if it doesn't work out.
My LBS has worked out good for me, and I've supported them with recommendations to others. They also don't charge me for small items like cable ferrules and end caps when a I want a few.