You might watch craigslist or ebay for used zip dee's I've seen them on Craigslist a few times. If you're up for a project, I think you could cut a longer tube down to fit your trailer (though it doesn't get much longer than yours
). Or purchase a new tube from Zip-Dee to attach to second hand hardware. We bought a new one from Lewster (forums member) and were very happy with his expert knowledge.