As promised, Xtracycle put their longtail bike frame specifications online as part of their project to open source their longtail frame design. They’ve created a Longtail Standard and logoing to allow vendors to design their products to fit in the Xtracycle Free Radical ecosystem. The Longtail Logo can be used on bikes, accessories or packaging.
Xtracycle has already approached the other existing longtail bike manufacturers about this standard and, according to Xtracycle, they’ve gotten a mostly positive response from them.