So why not roll with that?
I went to the office and found some old CD cases and dismantled them down to the clear plastic and set them up side-by-side.
You can then print whatever you want on sheets of regular paper and slide those into the CD cases. They're designed for you to print paper and put them in there!
It's the easiest DIY DM's screen ever: just print (or draw!) whatever you want on some sheets of paper and slide them into the CD cases. If you use a wide piece of paper you can hold the 2 CD cases together making a DM's screen with them.
Close the CD cases and you have a screen that's portable enough to fit in your bag.
There's tons of CD case templates on your computer in whatever word processor program you have - so use those to get started printing your rules, pictures, or whatever you want on the panels.
If you make a DIY CD Case DM's screen, make sure to post a link to a pic in the comments! :)
UPDATE: Here are some photos of the CD DM Screen with artwork. :)