I was so intrigued by the Toshiba U840W that I picked one up used on Ebay. It’s flawed, but the form factor is absolutely amazing and absolutely unique. The ultrawide aspect ratio is freaking incredible for side by side document comparison, and makes the laptop much easier to use on the go as it handles incredibly well. Downsides to the Toshiba are a low res TN display that utterly lets it down, and a keyboard that is supremely spongy and not very nice to type on.
Challenges I can see are that the display is likely something that would be unique to the device and thus prohibitively expensive to produce. Also, no idea if the laptop would appeal to the general public. Just because I think it’s cool doesn’t mean everyone else does.