All suggestions are good ones. The biggest thing I got from Cooper's book was the idea of flanking your entry ways with openings that allow you to observe/challenge anyone at the door. Sad to say, most designs neglect this aspect. Mine sure does..
I also like the idea of log homes. I recently tested a representative timber and was pleased that it stopped all handgun rounds. Rifles and shotgun slugs walked through it, but I imagine a Kevlar/Spectre/steel lining would drasticly improve the odds. Sandwich something more durable between the logs and the inner wall at least at your firing ports and you'd have a decent imitation of a bunker.
Giz