Footbar x-tension. If you're more than about 170cm (5' 8'') this may make your X-sail a little more comfortable. You can stretch out with you feet out the front of the chassis. It's held in place with a quick release bolt, and takes just a few minutes to fit. It'll make you more streamlined as well, for those record attempts.
This footrest fits the X-sail, and some other mini-landyachts with a 38mm keel tube. It is made of stainless steel, and attaches very quickly