When I moved my bottom bracket to the top of the beam, I had problems with chain contact on the frame. Primarily, the quick releases that allow the rear to fold. I also liked having a bottom chain run idler, (see Jack Williams website) because the long slack of the bottom run can autoshift at times or throw the chain.
I found a used skateboard at a neighbor's garage sale, chucked the wheels into my Shopsmith, and machined them down to pulley shape. Using a variety of bolts, washers and bushings for mounting axles, I used an existing hole in the frame for the top idler, and my original idler bracket for the lower. One is to support the lower chain run, and the top prevents frame contact. The picture also shows how I ran the front derailuer cable. I used small cable clips and pop riveted them to 1/8" holes in the frame, utilizing the holes that were existing for the chain guard.
the beam bag is from hostel shop, and i think it is bikee brand, but i removed any labels showing that. i like it better than my rear 'rack box' since its quiet, lighter, and holds the a same amount of stuff. it also took away the 'rear end wobble' that the rear carrier exhibited. Feel free to contact me if you have any questions!"