Begin dictation.
Please let me stick in my two cents.
Yes, in a word the answer is NO.
However, many people enjoy building things asked a hobby. Even things that are difficult or lacking commercial value. What I mean is that if an individual build computers at home and sold them to other people he could make a reasonable profit if he could keep his cost down. Although that is the case perhaps for desktop computers, is not the case for laptop computers. Still, there can be a compelling reason to do it anyway.
The compelling reason is the satisfaction one gets out of doing something that was considered very difficult. With current technology it would be very difficult for a homebuilder to fabricate a motherboard himself. However, he could purchase a replacement motherboard and then customize a case for the motherboard and add the other necessary components. There is room for improvement, modification, innovation and novelty in the details of the case and the connectors and the overall presentation.
To illustrate: how about a laptop where the screen display can be swiveled up into a position that is much closer to the user's face. This would be an important feature for people that have low vision problems. Or for people that are working on some unusual things. I'm thinking of someone who is designing fonts. They would like to have the screen very close to their face so they can examine the font with a magnifying glass. That's easy to do with a desktop computer, almost impossible with a laptop unless you do something funny, like put the laptop in a special cradle.
There could be other reasons for doing a custom laptop. Perhaps for some industrial and commercial applications a laptop is the only suitable device they could use it, yet it must be modified for special environment.
Replacement parts for laptops are abundant on eBay. It is almost like a junkyard. Car rebuilders used junkyards to find parts to make custom cars, therefore a home computer builder might find eBay to be a suitable junkyard for laptop computer parts.
Just a thought. Really, a person does not have to have great skill and knowledge to undertake such a project. Just persistence and motivation and some help from other people. Nowadays one of the things the Internet offers is the ability to connect with other people that have the same interests. Even if they're only 300 people in the whole world but wanted to build their own laptop, that would be enough to have a very active community of users helping each other.
Just a thought.
This is the end of the dictation here. The above may have grimmer issues. It was done by dictation. I have low-vision and I haven to be within six inches of the screen to see with my one eye. 
