The only reliable new coaster hub available now is the shimano cb e-110.
All the cheap bikes usually come with hi stop, falcon, kt, or some other china junk that looks similar to the shimano, but they're all garbage.
Not only do the bearings fail, but the brake guts blow up, the hub shells crack, wear out the bearing races, and are just plain lousy.
If you're just building a simple cruiser, a coaster brake alone is usually ok. It's always a good idea to have a front brake, though.
With a coaster brake, if your pedal chain falls off, you ain't stopping til you hit something.
And always, always, always, make sure the brake arm is strapped to the frame and tight.
Check Husky Industrial bikes for a reasonably priced set of heavy duty wheels. You can get a front drum brake which always looks good on a cruiser.