>The real payoff, if it is true, is that I'm told that such bees
>tolerate multiple queens.

Allen,
I have seen this many times. We mark the queens so that we can tell
if they have been superceded. Often the marked queen and her daughter
are present. I have requeened hives and discovered three laying
queens.  I have combined colonies and had two marked queens
cohabiting for months. The idea that there is always only one queen
is erroneous.

As far as workers raising queens, I have never heard that this is a
good thing, but we don't want supersedure in our hives in any case.
Now, I have been in beekeeping long enough to know that supersedure
queens can be excellent in terms of vigor and longevity, but in a
breeding program where you are trying to control the type of bee you
maintain (hygienic or whatever) they are a pain in the ass.

PB