I think your choice is right. The Malibu is a nice car with plenty of strengths- though towing isn't one of them.
The C10 is the obvious choice. I would also keep an eye out for an old Deville. Often you can find old Cadillacs which are well kept for reasonable dollars. They'll have a 472 or 500ci engine, big brakes, a/c and power everything. You ca but a bolt on class 3 hitch too. Drop top or not, you can't go wrong.
http://bringatrailer.com/2014/03/26/...sedan-deville/