The kneeler is an area that takes a lot if not most of the weight from the rider. Material for this was found in scrap bins. We found 2"x2" box tubing scrap and cut triangle segments off of either side to get the structure seen in the photo. Then 4" x 4" x 3/8" thick steel plate and welded them to the box tubing. We strongly recommend not using pegs or round tubing for kneelers, your shin bones will agree. The idea is to have a wide surface area to distribute the energy from bumps.
Minicel L200 also known as Y20 was used for the kneeler padding. This foam is resilient and has excellent shock absorption abilities. A generous two inch thick piece was used to eliminate the chance of ever feeling any hard shock through the knee or shin. Other foams that would work well would be neoprene or sleeping pad material. Minicel can be purchased at http://www.foambymail.com/Minicel.html