Bose tried to exploit the reflected sound concept that their model 901s made famous. The model 501 and 301 were somewhat successful. However, the reflecting concept has mostly been discarded over the following years. The Bose products also had a limited frequency range especially on the top end and they were not known for using high quality drivers. The model 901s were always considered their top loudspeaker and a few years ago they dropped them from their lineup.
Items you might consider would be the OHM omni loudspeaker but note they have a full and extended top end (talk to OHM about what you are trying to do). Next I would look at series one 901 (the best version). Replacement drivers are available but they have cloth surrounds, so they hold up pretty well. Make sure it has the right equalizer for series one.