...yes, I saw multiple such screens. I want a large screen and I do want to learn something, i.e. how to actually turn this into a product. I can't seriously buy these pre-made touch screens and sell them as a product with an RPi.
Plenty of commercial systems are bolted-together, commercial-off-the-shelf components or whole products. How many small shops have you swiped a credit card at, and their "register" was an iPad in a stand? Doing so lets you focus on the actual core competency of your business or product. If you're worrying about what some unknown customer might think about the appearance of your product at this stage, you're not focusing on the product itself.