I don't want to be scooping up chips and chunks of concrete when the soil
shifts and the uneven pressure cracks it. I can't see using rebar or
chicken wire OVER the liner to help stabilize the concrete.

You can use the wire. Check http://www.wetwebmedia.com. Bob Fenner, who
runs the place, operated a pond business for years here using just this
technique.

Still, I don't see any real problem with putting the liner over the concrete
if you're so inclined. You might ask Bob what he thinks of that; he
answers questions very quickly.

Also, the alkalinity problems caused by concrete

You use a plastic cement; even then you have to cure the pond. Often
one runs vinegar through it for a while.

C//