They're always been a little hard to come by. Contact online vendors when you're ready for one or if you have an LFS, get them to keep an eye out on the list. It can take a bit to find. Often you'll see little ones from the Gulf and Florida as hitchhikers removed from rock. It's very VERY rare to find a peacock that way. Some of the Florida rock seems lousy with the smaller ones, to the point it's an actual problem.
No one is successfully breeding them.
All our kids kept their own mantis over the years. Their tanks were smaller, so all had smaller species than the peacock, as the Peacock is rather large. They also like the bright colors of the other species. You don't need an acrylic tank, just don't get a cheap 10 tank and a large powerful mantis, such as the chiragra. You'll always hear about "tank smashers", but when have you actually read of that happening? The side panels are not what's at risk, at any rate, it's the bottom. When that meet up with the bottom, that don't know it's not more rock and try to pound their way through it to build their tunnels. If you put a sheet of acrylic on the bottom, they hit that instead of the glass. But seriously, I don't know how necessary that is, because it just doesn't happen.
We've kept about 5 species and I have to admit my favorite was the peacock, as far as personality. If i were to get another, it would be that species.