Here is a guys site http://www.ameetecarms.com that I have purchase stripped uppers and lowers from. I don't think he does Kali safe stuff, but his parts are good to go. The owners name is Warren, he a pretty reasonable guy. He sells complete stuff too.

AR's are fun and relatively easy to build. My advice would be to keep the rifle simple. Below you will see a pic of one of my AR configurations from the past where I lost my mind and hung everything tactical item I could off of it. Kind of defeated the purpose of a carbine which I knew but did it anyway. It was a cool theory I had though.