After agreeing with Kal, my first question would be: What are you biamping?
If it's a 2-way, the passive at about 2KHz probably isn't as "awful" as you think and an "off-the-shelf" active crossover can be just as bad or worse. Besides, the power required above that is minimal. Ribbon tweeters usually require passive filters or, at minimum, a capacitor for protection.
If it's 3 (or more)-way, and the crossover is below 400Hz, active biamping becomes more reasonable. It's when you get down to 100Hz, and the inductors start looking like toroidal transformers, that active biamping really pays off. The problem with that is all the passive crossovers in the speaker are usually on a single PCB.
If it's a 2-way, the passive at about 2KHz probably isn't as "awful" as you think and an "off-the-shelf" active crossover can be just as bad or worse. Besides, the power required above that is minimal. Ribbon tweeters usually require passive filters or, at minimum, a capacitor for protection.
If it's 3 (or more)-way, and the crossover is below 400Hz, active biamping becomes more reasonable. It's when you get down to 100Hz, and the inductors start looking like toroidal transformers, that active biamping really pays off. The problem with that is all the passive crossovers in the speaker are usually on a single PCB.