Not easily done at all. Many vehicle controls and systems are under the floor not to mention the structural members involved. Consider, Shift linkage mounts and control rod routing, Air brake valve and lines. Throttle pedal mounts-linkages-cable routing, Steering gear box mounted under the floor and various other components carrying the motion to the steering wheel and much more. Not to mention the dash and instrument/switch clusters having to be raised in order to retain any semblance of a usable or proper driver to controls geometry and human factors engineering interface. Way too many variables to rationally consider this. Coaches have a raised passenger level to increase the height for the under floor luggage compartments. If you don't like the driver position then you might consider getting a Transit bus with a typical low floor configuration where the driver shares the same level as the passengers, which is obviously what you seek, or a School bus of some kind. As I've always said.... Coaches are different for many reasons and usually much more expensive and proprietary in nature. They're designed for a type of service and those of us who choose to convert them must accept the reality of their inherent layout and adapt that to our new service paradigm without destroying the underlying vehicle reliability, functionality or usability in the process.