If you want carbon fiber gear legs, try extremeflightrc.com. Although they do not specify the dimensions, they do specify the wing span and the kit for which they apply. Not cheap, but strong. At the website, type in a search for "landing gear" and look for a plane with a 70 -72 inch wingspan. That should be close. They have a gear for a 70" Extra 300 for $57 listed on page 6 of the gear pages that might work.