I don't think brubacca is thinking of there being a crossover at the amp (if so, then there would be a simple but effectively insurmountable obstacle - crossover designs need to be customized for the speaker they are used with, making a "global" crossover package almost useless), but rather of providing separate amps that would each get and pass along a full-range signal. This would leave the crossover duties at the speaker, and would make this a passive bi-amp arrangement. The market for it would definitely be small, probably not enough to make it a viable product.

What would be an interesting intellectual exercise and probably an equally doomed commercial product would be a modular arrangement of brubacca's amp with interchangeable analog crossover circuits immediately upstream of each amp, thereby allowing you to "plug in" the appropriate high pass and low pass crossovers for your particular speakers. Of course, you'd also have to go into your speakers and bypass the existing crossovers there, and the process of developing and supporting the hundreds of different speaker-specific crossover modules would be frightfully difficult to even begin to develop. Maybe combine Brubacca's 3x125+3x60 amp with a matching chassis equipped to accept three inputs and split each to an empty workspace where a savvy consumer could build and install their own crossover network - the companion "crossover" chassis would then output six signals to the amp.