Hello Brad & All,
> My question is two fold:  first, how much wind does it take to blow hives
> over that are 4 deeps high
The wind you describe is enough at times.  Hive can take quite a bit of wind
if they are not tilted to the front.  Many times we brace two queen hives
with 2X4 's when 4 deeps high.  Brace like you would a pole when building a
pole barn.
> and two, I am thinking of moving the hives  off the crest and down on the
>leeward side of the slope near a tree line  this winter.  In so doing,
though, <they would not get sun on the hive until  a couple hours later in
the morning >>(9:00-10:00ish).
I would move the hives off the crest of the hill or provide a winter wind
break. Your honey crops are similar to ours in Missouri and the bees getting
started by 9:00 _ 10:00 is ok. If you were concerned about pollination of a
certain crop my answer could be different. I see bees being able to fly
early to pollinate apples as a plus. Many times all apple pollination is
done in a couple days because of inclement weather in our area and a couple
hours of extra pollinating time helps.
I have got a close beekeeping friend in your area. We spend hours talking
about our bees and the differences between Nebraska and Missouri.  Wintering
in your area of Nebraska is tough. My friend and the other Nebraska
beekeepers I have met migrate south each winter.  I believe you will get a
decent honey crop most years but might have trouble wintering. I would make
wintering my first priority.
Sincerely,
Bob Harrison
Odessa, Missouri