This is one of those ideas that is so simple I wondered why I didn't think of this! I got this from Judy Ellis. You get a tri fold cardboard display board, cut out high frequency words, laminate, and Velcro them to the board. The result is a word wall that can be moved anywhere in the room.
I chose to leave the background white and cut the words out of multi-colored index cards. The Velcro sticks well to the display board without ripping it. I only display the words that we have covered in class. I add new words after they have been introduced during class time. At the end of the year I can remove all the words and save them for the next year.
During independent work time my students are scattered throughout the room on pillows and at tables. They can't always see the main word wall so it is very nice that they can bring this one wherever they are working.