Purchase Bob Books in their current format (little books in a box). Purchase a 2" CD clamshell from your favorite library supply company. (Demco product number WE15305260 is 2" and includes an outer vinyl sleeve.)
Recycle or discard the CD sleeves. Punch the Bob Books to fit the two metal binder rings, and bind into the clamshell.
Then, simply cut the Bob Books box apart, and insert the disassembled box sides into the outer vinyl sleeve.The box front fits in front, the left spine fits in the spine, and there is just enough room to fit the right spine and the back into the back sleeve.