The Parts Express 901 replacement driver is $18.75 ea. in quantity, less than 1/3 of what Bose charges for an OEM driver. So the drivers are probably worth around $10-11 each wholesale. The Parts Express drivers appear to have about the same build quaiity.
I'd like to see what you could get with 10 higher quality full range drivers in a different configuration such as a tower with 8 drivers facing forward and 2 facing rearward for ambience. The larger cabinet should provide better bass performance with less EQ, and the 80/20 ratio would provide better imaging with more direct and less reflected sound. You'd retain the advantages of the 901 with fewer of the drawbacks--crossoverless sound, large radiating surface, but with more optimized cabinet and more realistic dispersion pattern.
Many of the newer full range drivers have phase plugs, which should improve high frequency dispersion, though you'd probably want to angle the drivers somewhat to improve it.
I'd like to see what you could get with 10 higher quality full range drivers in a different configuration such as a tower with 8 drivers facing forward and 2 facing rearward for ambience. The larger cabinet should provide better bass performance with less EQ, and the 80/20 ratio would provide better imaging with more direct and less reflected sound. You'd retain the advantages of the 901 with fewer of the drawbacks--crossoverless sound, large radiating surface, but with more optimized cabinet and more realistic dispersion pattern.
Many of the newer full range drivers have phase plugs, which should improve high frequency dispersion, though you'd probably want to angle the drivers somewhat to improve it.