your post is just a tiny bit unclear...if taken literally, you already have the retract and just need a strut? Is it a 1/2 " trunion?

That's an fairly long strut, even for the jet community. contact this outfit [link]http://www.sierragiant.com/[/link] and see what he can do for you. He does top-notch work. I hope I'm wrong but that seems like a custom request to me and might be expensive, but there's no telling until you ask, right?

Hope I helped, Don.