I used to use a Kindle to carry around a mini portfolio while out and about. It was kind of inconvenient due to the slow start up and size. While not very big, it still is a lot bigger than a pocket portfolio. I found myself not having it with me all the time when it was needed.
I decided to switch over to mini prints for portable portfolios and retired the Kindle. Our family has 4 vehicles, each vehicle has a pocket portfolio in the glove box. So I always have something with me if I need to show my work. See if a pocket portfolio would fit your needs.
Here is the first experimental one I made in 2013. I have graduated to a slicker design now with duo lustre paper.