Yes I do. I have darks and Jubilee (white mixed with dark) and one white hen. I really need to get on breeding this year.
They aren't fast growers, but they make a nice meaty carcass whenever to decide to butcher them. You can grow them out to individual meal size (for one person) at about 12 weeks. You need to grow them out to at least 16-26 weeks if you want a decent sized bird.
Unfortunately, I doubt I'll have any extra eggs for sale this year.
One tip, if you find hatchery Cornish, DO NOT buy them unless you are looking for a different looking egg layer. Hatcheries do NOT do a good job maintaining the meat qualities of their heritage Cornish. A hatchery's job is to sell chicks, they get chicks from eggs, they make more money if their birds are better egg layers. So they major on egg laying and NOT on meat qualities. Instead, look for show breeders. That is the ticket for getting good meat birds. The SOP (Standard of Perfection) for Cornish is for a meat bird, so it is in the breeders' best interests to breed for meat qualities. That is where I got my original Dark trio