One place to check is Harbor Freight in North Kent or South Rention.

I think they have a 5x10 and if you needed to lengthen the tongue, go over to metal shorts in seattle and pick up a square tube, but youll want to mount it to the main frame beyond the wishbone. As long as you install bearing buddies and keep it grease, you should get at least five years out of the axle and bearings. I bought a smaller model and I ended up replacing the axle and springs with a 2000 # dexter after 5-6 years. Its nearly impossible to match the import seals and bearings. I think the tongue I bought was 2x2.5 inches. The hitch connector is the primary consideration. Technically, you need to get with the state patrol and they will stamp the numbers into the tongue, but you can buy a set of number stamps and tag the frame with the serial number. Keep the original tag or tongue for your records. 3-400 for the trailer. Use outdoor carpet for you toon covers. Plywood will slice it, sooner or later. Get complete spare tires at les Schwaab.