I'm no chicken breeder, but I have a friend who is breeding a dual-purpose chicken by crossing Rhode Island Reds with Bresse (a great meat breed from France). So far they seem to
be nice meaty birds that still lay well. The idea being that one gets a good carcass from them after they stop laying eggs so much, plus from the roosters.
And yes Rhode Island Reds were originally described as dual-purpose, but the modern lines have largely been bred for egg-laying. Perhaps there are still more traditional ilnes out there.