Are there speaker stands that are continuously adjustable? Some of the stands sold as adjustable stands seem to have presets.
The Sound Anchor Adjustable Studio Stands are and the speaker platform can be rotated 90 degrees. I think they are the best audio investment I've yet to make.

Sound Anchor Studio Adjustable Stands

I bought the stands for use with M&K S-150THX monitors (basically a 12" cube). They are now supporting a pair of JBL LSR4328 monitors, which are more rectangluar. Being able to rotate the speaker platform is a huge advantage. I can send you some pics if you like.
Check out the models from Core on the 'Gon. Simply enter "Core" in the search box and various models will come up. They are really very nice (some are adjustable too).