The solution is an inverter per cell. All MPPT logic and power conditioning should be done in a small module (chip?) associated with each cell. The output from these small inverters would be combined on a panel to produce a single output from the panel. All panels should be connected in parallel. Shading, etc., would only affect the output from the shaded area. Multiple orientations would be a no-brainer. Additions to the system could be done in single panel units, and they would not need to be size matched to the rest of the units.