May take her a while perhaps. My understanding is that she is farming out different aspect to different fab companies. This is highly inefficient and opens the door to MANY mistakes from several different vectors. She would be better served to hire a good fabricator or two and do everything in house. I am assuming she has purchased all the jigs and related fabrication aids. As such her valuable property is in others hands. These hands might get an itch to start building carts, even a different cart, that they otherwise would not have had. Lastly, she should learn every aspect of building her product, from straight stock to rolling off the showroom floor. This the ONLY way she will know her product in a very "biblical" sense and also when things change or otherwise become "out of spec". This tactic has served me and other good builders for a very long time. Following the KISS principal, it would appear that she has not set herself up for simple and again is inviting a host of problems that are not necessary. Even setting yourself up for simplicity will still bring a world of hurt, just being in this industry. I do hope she does well.
Bb
Graham Carriage Works (.com)