Since you are grafting frame rails to an existing chassis i would get a frontend kit with rails and suspension. Since you enjoy the building have a look at what canadian Paul Horton sells - they can be found as 'welders series' in google. They make the raw materials for a number of outlets but will sell direct and you build it yourself. Check them out, even if you stick with your existing plan these guys will impress you and they have a bunch of items you might be interested in using.