Wouldn't that just be a straight up design/branding firm?
It is far easier to pick a random name and match it with some random generic branding, than to be given MySpecificProduct.com and build a brand around that. Branding companies charge a lot of money because it (generally) takes a lot of time, effort and expertise to build good brands.
There is also the fact that it would become a designer-client relationship than a merchant-customer one. Clients get to dictate what they want (to a certain extent), customers see what they are getting before they buy. What if they built a brand around MySpecificProduct.com and you didn't like it?