Honestly, as a part time business owner and working the trades for most of my life, if there is anything I have learned it's that your quality of work will always speak for itself. If you are good at what you do and create perfection everytime, reputation will come naturally. I have very much thought about selling my own racks as it's very easy for me to do. I built my own PVC racks and it went really well. The joints are perfect, its square, its strong and it looks good. What more could you ask for. The hardest part I had when I first started contracting was convincing a customer that I am competent at doing the work. Especially being a 22 year old kid. This was because of my lack of a portfolio so the first few jobs I only made 25-50% profit. Now it's much higher however when I quote a job I can show them very close examples of MY work, not come good searched work that it "will look close to this".
My part time company is a hobby but of course I like having the supplemented income of the work. Just don't get into this thinking you can half ass the craftsmanship. If the words "close enough" ever come out of your mouth, just re do it. Believe me you will be glad you did it in the long run and in a market as saturated as it is with good workmanship, you will fall to the side if you decide to cut corners.
Just my 2 cents, I love seeing guys try to start up things like this.