Check out Del-Ton, Inc. A complete line of AR-15 Rifles, AR 15 Parts and AR15 Accessories. I have dealt with them in the past The sky is the limit ..
Just fyi, Brownells has an excellent series of videos that walks you through building an AR from the ground up, and details everything involved. They are available to watch online for free here:
Brownells - World's Largest Supplier of Firearm Accessories and Gunsmithing Tools
It's nice seeing someone actually perform the steps and assemble the gun as opposed to just reading about it. I'll say this much, assembling AR lowers looks like child's play to me now.
An AR-10 chambered in .308 makes a lot more sense (one round is a man stopper, will shoot through most cover, and can make a good deer rifle) but if you want an AR-15 pop-gun, consider a Texas made upper.
Welcome to Model 1 Sales' Online Order Center
Are you the owner of Model 1 Sales? Have a store location? I'd like to ride over one day and visit if so.
Let me know. Thanks.