Quote - Err... Poser 8 does just that with IDL turned on and an ambient setting (former versions just had the object glow without emmiting light)... So the question is: why reinvent the wheel (and add corners)?

Because it's not a wheel.
Lux area lights are real lights, not just faked ones. You can have different types of area lights in Lux, like black body, spectral, RGB ones. They have the same attributes a "light" light has.

That been said, and since it is faked with Ambient inside Poser, the best solution would be to tie this to a given material. You just have to make sure the user can edit this material to make it a real area light in Lux.