I just bought my new 223 DPMS 2 days ago. I decided on the panther Bull 20. It turns out my gunsmith who is working on my custom hunting rifle is a dealer for DPMS. He was able to order the parts from various suppliers (223 bull barrel upper, stripped lower receiver, Jard trigger, etc.), receive them, and put the gun together in 5 days. It was also about $200-300 cheaper than my local sporting goods store.
If you don't mind paying more money by replacing a few parts on the rifle, then DPMS doesn't have to "custom build" your rifle which takes at least 3 months. (They "custom build" all their rifles ordered directly.)
I'd look for a private dealer for DPMS (or other company for that matter), or try buy the closest model pre-built if you are in a hurry, and just replace the parts you want. I hope this helps.