Hello
I'm a G&W collector from Spain.
A few days ago I designed a "construction paper" (thin cardboard) stand for my Multi Screen G&W games. All you have to do is to print this into an A4 sized cardboard, cut and glue. Alternatively, if your printer does not accept cardboard, you can print it into an A4 normal sheet, then align the paper with a construction paper, and cut together both sheets. Then you throw away the paper and keep the cardboard. The stand is able to hold a G&W only if it's made from construction paper, otherwise it will bend. I find the final result so stable that I am surprised it worked the first time.
This is for Book Type Multi Screen games. Although it also works for Donkey Kong, Green House, etc,.. they won't fit well. I will soon design another one for those.
Hope you find it interesting.
Link to the template
Link to the final result