Okay, a suggestion:
I was thrilled to see that the X5 has a balance control. My hearing isn't perfect and I have a slight deficit in my right ear -- a balance control would let me compensate a bit. However, balance only works on the X5's internal amplifier and has no effect on line out. As I want to listen to my X5 through my E12 amp, the balance control offers no benefit. Any chance of putting it ahead of the amplification stage, rather than after it?
I understand why you would want this, but doesn't that defy "line out" as a concept?