I know some people who are experimenting with those Highlanders. I don't think they would favor are hot summers though. Maybe a low percentage would not be so bad, say less then 12-20 percent highlander cow and keep the hairiess ones to make cows. You could then put a Hairy THC clubby bull on them and voila.
There have been quite a few winning steers over the years in Canadian steer shows that were about 1/4 Highland blood. Highland crosses are exceptional in carcass competitions as they have excellent marbling and cover so well. Another breed to consider are the Galloway especially if you want a good bunch of clubbie moms. Some of the winning Galloway bulls and females are really quite awesome, and they cross real well with Angus cows to give you a black moderate framed female that milks extremely well, and puts some extra hair on her calves. Breed these cows to some of the clubbie bulls, and you could be off to the races. I have seen some of these calves and they are actually quite sound in their make up besides having crazy amounts of hair. As for raising these cows in southern clims., I know there are lots of Galloways in this country that used to sell to Texas. Both the Highland and Galloway are very hardy animals that probably have more ability to adapt to their situation better than any other breeds.
Daines Hairy Crumb had a little popularity for awhile. He was a Power Plant out of Daines Miss Hairy who was 1/2 MA and I believe 1/4 Angus and 1/4 Galloway - could've been 1/2 MA and 1/2 Galloway though, I can't remember for sure. They also had some other bulls out of that cow, 1 out of Cunia that they promoted some, too.
The Hairy Crumb calves were nice haired, but his biggest claim to fame was that he was a really good calving ease sire. I still have a couple of clients that use him on heifers and they like his daughters alot.
Calving ease... another proof there's Galloway in his pedigree. As far as heat resistance, I think a lot of you are wrong onyour assertions that either of these types don't acclimate to warmer climates. JIT is right.