Robert,  some of the best queens you can find have been inseminated from
multiple
races.  Most queens take donors from 6-8 drones, some upwards of 15-16
(according to my queen rearing info).

My experience is that hives with varying race do well and sometimes
produce immense hives.   Some are not so hot.  Overall queens producing
varied offspring seem easy to manage and adaptable, but I doubt you
could select any particular charicteristic into a breeding program
without first defining race.

What's funny is the distinction in colors seem to disappear after the
first year - or perhaps it's because I don't normally pay attention to
breed once a hive is properly established.  There's one hive with a
'beady' black queen I remember in particular, that gave up carniolan
bees(grey) along with solid black bees - and I visited that hive a few
days ago and found the bees are nearly solid carniolan.  The queen may
have been replaced by now.  Just as a side  point, that hive was
over-wintered with 1 & 1/2 frames (!) inside a nuc placed outside a
window at my house.  This is no small challenge in my neck of the
woods.  If interested, check out the photos at
(  http://www.beesource.com/eob/nucs.htm  ).

ROBBERS:
A good way to tell if you have robbers is to watch how the bees land.
Robbers will usually sway from side to side (without a change by you to
the entrance) and walk in very timidly.  Watch the landing board for
defensive bees.  If you have bees
checking the smell/taste of every bee landing, your hive probably isn't
being robbed.
If you're still unsure, pop out the lowest frames of honey and look for
evidence
of robbing - jagged tears from bees ripping off cappings.  Find nice
neat comb and you can be certain the hive isn't being robbed.

Matthew Westall - Castle Rock, CO