My Silkies are about the same, around 5-6 eggs a week. Sometimes more, sometimes less. Their poor production wrap is because of their tendency to go broody. And that pretty much goes for most bantams. You can get bantam Leghorns and Rhode Island Reds, but don't expect to lay as well as their standard sized counterparts. Bantam Orpingtons are nice birds, but they like to brood as well.
If you go with Silkies, I think you'll be surprised by how well they lay. And if/when they go broody, if you don't want chicks, you can always break them to get them laying again sooner.
One draw back of Silkies, they tend to take a long time to mature and they're very difficult to sex. Especially if you get birds from a breeder.
