[Kevin Sevcik]

From a more practical standpoint, if you make that entire shaft spin, you'll be putting a terribly large load on the bearings and shaft. Ball bearings are intended to support mostly radial loads. With your current design, the shaft bearing at the top would see a large thrust load, which would drastically shorten the bearing's life if you don't over-spec the bearing by a lot. Also, keep in mind that flexible shafts aren't going to transmit much torque.