Well i would think that just about anyone that it welding trailers could custom make you one like this depending where your located my xbrother in law (we still hang together) can bild you a trailer to suit whatever needes you have .email me and i'll hook you up. by the way were in col. ga
Check out http://www.hhtrailer.com I have purchased two H&H trailers and have ordered a third. Great quality, good price, excellent trailers. They do have a side ramp option and you can specify the size.