I just made myself a design wall, too. I used a plastic flannel backed table cloth and velcro. Velcro is on the top of the blinds (not actually on the blinds)in one of the rooms our grandkids use when they come. It works well. If you decide to do this, though, make sure you get a strong velcro. If the velcro isn't strong enough, your design wall will fall down. I found that out the hard way. When the kids come, I can take the design wall down, roll it up and store it in the garage.
I know you will enjoy having a design wall. It makes a very big difference for me!