Did you notice? Since 4/5 years more & more professional & garage builders use an old Iron Sportster or a new Sportster/Buell powerplant to build their custom choppers. Since 1 year, we even see more Sportster drivetrains installed on new built Bobbers. But there were few people in the industry building cool aftermarket Sportster frames. In addition to Atlas Precision (who never stopped building one), 2 of the new frame builders making such an offering are Red Neck Engineering & Twisted Choppers. Personally, I like the Sporster/Buell rolling chassis of the guys of Twisted Choppers in South Dakota. Simple, clean, and affordable. They offer many options for the frame itself (stretch & rake), for the size of the rear wheel, and for the front end, hydraulic or Springer type, and they provide the custom gas tank, oil bag and battery box fitted to their frames. Twisted Choppers.