Thought it was too good to be true - I know plenty of Game Engine coders from my original days of Quake .. yeah back then
so I know how hard something like that can be.
I've counted about 20 mods people are "working on" but the only person to ever send me anything to look at was a Half Life Mod of the SGC with a working Gate. It's kinda cool, but not much to shoot at when you've blown all the computers up.
It's available from my site to download from the Half Life SG-1 section under the Community heading.
The guy who did that changed his email and I've never been able to track him down since. Permission was granted for me to post his work so far though.
Here are some pictures from a Half Life mod that is no more
http://home.earthlink.net/~mrbatman/hlmod.htm
Here are some more links I picked up off google.
Quake Engine
http://www.planetquake.com/quakarium/stargate/mod.html - Suberb graphics but nothing in the way of downloads yet.
Half Life Engine
http://mod.famkos.com/ which appears to have been stopped by MGM - fancy asking permission
Duke Nukem
http://www.totalconversions.com/info/download.html - The most complete with an actual Beta Download.
Tribes 2 Conversion
http://www.planettribes.com/sg1/ - Again nice screenshots but no real downloads yet ...
One thing for sure, whomever comes up with a Stargate SG-1 game that's any good is onto a winner !
If I were the Mod Designers I'd badge it as something else but base it on the Stargate Universe. That way the PTB can't be as mean