[Phantom]

What could be done to help eliminate the issue of additional pressure/pumping loss from the deactivated cylinder is:
Remove the exhaust valve
Reroute the exhaust on those cylinders to open air

If you cant keep the spring in place to push back on the rocker this will not work and would not allow you to turn them on and off. By opening the exhaust side to open air it eliminates the compression of air and prevents it from slowing the expansion stroke of the firing piston. Also this will prevent the O2 sensor from seeing the extra air.

Plus it could sound cool.