We have a mentor that does a decent amount of sewing and have had the students do reversible bumpers in house the last few years, similar to the RoboPromo kit:
http://www.robopromo.com/product_p/rp-2004.htm
The video at the bottom of the page does a decent job of walking through the process. Words of caution, make sure they are centered vertically on the board, as tight on the board as possible and that the Velcro on top and bottom has several staples through it. That keeps the Velcro from loosening due to movement of the cloth on the wood backing. Also we use full strips of Velcro at on the top and bottom.
This allows us to permanently mount the bumpers.