As I mentioned, you will not see the full benefit nor will you lower your speaker's resale value unless you remove the crossover. This approach will always generate debate much like vertical biampping, since it uses ideas from both active and passive biamping. I would say there is a continuum of sound quality/cost which runs along these lines.
1) Standard setup, one channel per speaker
2) Vertical biamping, two channels per speaker Need more amps
3) Active/Vertical biamp approach (This one) Need more amps and a unusual crossover.
4) True active More amps, crossovers and speaker mods.
There are a few who stoutly maintain that passive biamping has no effect and will not improve your sound, since I've heard it improve sound, to the point where I bought another amplifier for that improvement, I disagree with them.
There are two main advantages to an active biamp over other forms of biamping.
1) "Getting passive filters out of the way" and thereby getting rid of all the nastiness like phase shifts and frequency response problems which passive crossovers are noted for.
2) Reducing the frequency range of the signal each amplifier channel is seeing. With a vertical biamp, the amplifier still sees the full frequency spectrum and attempts to reproduce it even though the portion of the spectrum which is outside of it's section of the speaker does not produce power since it is driving infinite resistance.
You will not get the first benefit with the approach I suggested, however you will get the benefits of reducing the frequency range each amplifier is seeing, and keep it from trying to reproduce the singal which will not be heard. Exactly how much of a benefit you will see is somewhat system dependent, since it relies on the original crossover.
BTW - The Bryston I was referring to is the 10B, it's up on Bryston's web site at www.bryston.ca.