This system is not aimed at the individual chess player but chess tournament organizers or some other central organization that provides the scanning service at tournaments. The cost is very little, so it is possible to offer it as a free service.
The scoresheet used in the demo is 8.5" x 5.5" and has 32 moves; if the back is used, it can have 64 moves. A more compact design G64 (without source indicators) offers 64 moves per side for a total of 128 mover on 8.5"x5.5".
Optical mark recognition (using opencv library) is used to achieve predictable paper-to-electronic conversion. The scoresheet template in the demo supports the full chess notation.
Since moves are converted to electronic format, automated corrections of incomplete and incorrect scoresheets is possible, especially given 2 scoresheets of the same game (from the 2 players).
Here's a demo https://youtu.be/nc2n-UjrzpY
I envision a scanning station for players to scan their scoresheets (containing barcoded player tournament registration info) as they exit the tournament hall; this can provide automated game results and game PGN/analysis data to the players on the web.
Blank scoresheet
https://1drv.ms/b/s!AkjJO15BouadhTFDOkFAGzeIaR4x
Note: If you make a mistake, you can delete a ply by crossing out the "RNBQK", then re-enter from the next ply of the corresponding color. To denote promotion piece, you draw a line above (for white) or below (for black) the "RNBQ". Similarly, to enter the source square (file, rank, or both) you draw a line above/below. The "x" is optional, if you want to indicate it, put it between "K" and "a". OO and OOO are indicated by marking the R,K and the source R file.
Conversion program
https://1drv.ms/u/s!AkjJO15BouadhTLLJOQKoDYbCVr6
Note: This is a VirtualBox-exported virtual appliance. To use it, install VirtualBox and import it. Login/password is scoresheet/scoresheet
Here's a picture of the scoresheet I used in the demo. As you can see, I've made a mistake in move 6 so I deleted that ply.