Why do you want a coaster brake? All of the internal hubs come with good lever controlled hub brakes.
I personally prefer the SRAM 7sp hubs to the Shimano 8sp. They are a simpler design that is easier to work on. The gear spacing is more consistent. The range is about the same. They are more robust. You can get them with a drum brake, coaster brake, or no brake. I have the drum brake model on my Tikit.
alex