If you can wait a little bit, I am designing a crossmember similar to the CenPen, with what I feel are improvements. They use a sleeve bag which does not like to articulate, which is what those bars will make it do, so the bag may wear out within a year or so. The sleeve bags also have a soft spring rate, and I fear it may be too soft since they are mounted with a leverage ratio, and a heavy motor would probably mean you have to drive higher to get a firm enough ride ot not bottom out. I am designign one that will look similar I guess, but use what I feel is a superior bag that should ride better, and probably be cheaper.