Mike at Mike's Spot correctly identified the AR that I'm building as a MK12 Mod 0 Special Purpose Rifle. Wikipedia has some good information on their MK12 page if you want some background history, and if you have a hankering for some lustful MK12 SPR p0rn, look no further than ARCOM's MK12 picture thread.
I started this build for several reasons, the first and foremost being a tribute to troops who have used this type of weapon in combat. A close second is that I believe it to be the sexiest AR rifle in existence, and when my rifle is completed I will whisper sweet nothings in its ejection port and take it to the prom. It's that beautiful.
Since it started out as a clone, I have done my best to pick parts that are correct for the rifle. Sometimes it doesn't turn out like I wanted it; for instance I ordered the A.R.M.S. #40 folding rear sight, but I ended up with the #40L - the low profile version - which is not the correct sight, but is actually better in that it sits flat with the receiver. This means that I won't have any issues with mounting my scope forward of the sight. Other things like the lower receiver being from DPMS are not as important to me because I'm not going to spend a great deal more for a Colt or whatnot - not that there was a specific receiver when NSWC Crane built the things for SOCOM to begin with. I also went for the SWFA Super Sniper 3-9 scope instead of the Leupold MK4, as I am not going to spend twice as much for an inferior scope. In my opinion, the SS scope is more on par with Nightforce than Leupold anyways. If you have not seen SWFA's lineup of Super Sniper scopes, than you are missing out on some fine optics.
I'm still waiting on my bolt, barrel, and upper receiver from Les Baer, which I am setup to send to ADCO to profile it to take the OPS Inc 12th model muzzle brake and collar, and I have to pickup a bolt carrier and some A.R.M.S. #22 rings as well. In the meantime I stuck the PRI forearm on an upper that I had lying around, stuck it on top of the completed lower, mounted the scope on top with a Bobro mount, and did some dry firing. I'll have to post a pic when I get the chance.
There is still the question of what caliber this sexy beast is going to be chambered in. . . . . . .