Ribbon, planar magnetic, electrostatic omni-driver

You mean a planar driver replacing a typical cone omni driver? I dont think it would mate well really. The dispersion characteristics of omni's rely on ambiance effects. Planars need to be carefully aimed. The rear dispersion characteristics of planars add an ambiance effect in a way, but very differently compared to omni type dispersion.

Vandermeulen,
I mean for instance: take a look at the mbl drivers, instead of the leaves expanding and contracting from getting squeezed and relaxed by a motor they would be planar magnetic like the drivers found in the old infinitys. With the center containing sound absorbant material.
Any mbl fans would probably appeciate alternatives that will not break the bank.

I seriously doubt that MBL owners are worried about breaking the bank.

OHM had a omni type speaker for years.

IIRC, there was an IEEE article, maybe in the mid 1980's, on "coaxing" omni response from planars using a technique call something like Hoffman Encoding. AFAIK, it never went anywhere commercially. A couple of hours on google might get you the paper, though.

Marty