I have 2 5'ers, and one of them is tuned ADCGF. It's a 35" scale, so there's no floppiness whatsoever. Plus, I have active P'UPs so there really isn't any deadness in the A.
You can tune to Bb without a problem, unless, of course, you have a shortscale bass.
You can tune to Bb without a problem, unless, of course, you have a shortscale bass.