Hmm, Ronnie are you referring to the Ball Shifter with your question or the WCP shifter?
The WCP products are designed to house the sprockets between the plates
Single Speed Assembly in WCD configuration
Dual Speed Assembly in WCD configuration
The Ball Shifters are completely enclosed, so the sprockets need to be on the outside of the gearbox and also have some spacing away from the chassis rail itself. If you can solve that without an inner bearing block in the rail, then you don't need the inner bearing block.
Generally speaking, a single shaft should only be loaded between 2 precision bearings. The more bearings you add, the more chance the bearings are precisely lined up in their mounting leading to inefficiencies.
The WCP gearboxes use only two bearings on the output shaft - one is on the inner gearbox plate, the other is on the outer bearing block (there is no inner bearing block). Spacers on the hex shaft keep the sprockets in place along the axle. This allows the outer plate of the gearbox to be direct-mounted to the chassis rail as Andrew described.
Thus I believe if you're asking about the Ball Shifter, your question can be reduced to whether or not you can replace the bearing on the output shaft with a spacer, and then move that bearing to the outer bearing block. In theory I see no problems with this, yet I also don't know how the Ball Shifter is mounted.
I only know this because I did some pretty thorough research on the WCP SS gearbox in WCD configuration since it's the only WCD-designed gearbox that VEXPro has in stock at the moment and we want to prototype something this Fall.