Try EJ Jordan drivers (FX92? I think is the model). Jordan drivers are similar to Fostex and Lowther but for much less money and no 1000hz hump like lowthers. The are not as efficient as lowthers but still pretty good. Range is essentially 100hz to 15khz. The have a little lower bass but do roll off.
This is what 47 Labs uses in their ultra expensive systems.
This is what 47 Labs uses in their ultra expensive systems.