I never really understood the double bass issue.
If the issue is that you have the same bass signal delivered to multiple sources and that doubles the content, giving a unrealistic sound, then the only true solution is to have all information below a certian Hz delivered to a single driver in mono, right? I think that I am listening to "double bass" all the time, where the x-overs overlap in each speaker, when the sound is bouncing off the walls, where the recording is using the same information and sending it to the two stereo speakers to produce a centered sound stage, microphones in the sound recording picking up additional information in the studio...