An interesting correspondence, and one that brings back a lot of
memories.  I recall that a commercial beekeeper on Vancouver Island also
used a platform.  Perhaps Paul van Westendorp or John Gates will be
able to remember more about it.
 
The system Jerry Bromenshenk describes is also the one I remember
being used in southern British Columbia.  We used to construct such
bear fences for isolated queen mating yards and fireweed sites.  Getting
a good ground for the fence was also a problem for us, and the chicken
wire around the perimeter seemed to do a good job.  I also remember
hammering a six foot piece of reinforcing rod into the ground to improve
the current.  The fencers we used were Gallagher's, made in New
Zealand, and ran on a car battery.  Gallagher's also make a
solar-powered model.  We used to check the current (and ground) with
a nifty little LCD read-out meter (also Gallagher's).
 
Another system we used involved placing 4 or 8 colonies, together with
fresh honey supers, on a wooden pallet, and then wrapping the hives
and pallet with chain link fence.  We also cut a cap out of corresponding
size chain link to use as a top, and fastened both the cap and the wrap
with fencing wire.
 
The system worked quite well.  It was fairly easy to get into, was quick
to set up and take down (quicker than an electric fence), and was both
robust and completely reuseable (every year we seemed to have to buy
a few new pieces for the electric fences).
 
The system was also very bear-proof (if a bit puzzling to them).  I
remember once driving into a site and seeing two bears sitting on top of
one of these pallets, reaching down with their paws trying to figure out
how to get in.  The only damage we ever had was a few tooth marks on
the corners of several lids where the wood poked through the chain link.