Huang has what you're looking for. He has a CIRAS and MBSS available in OD. Check his thread in the retailers section. I've bought both the CB and OD CIRAS vests from him and they're good quality for replicas.
Saint makes a very good point about getting a hydration pack, especially if you're running a full vest like a CIRAS. You may find in the end that you're more comfortable with just a basic chest rig. You'll notice from pics here and around the net that folks end up going with what works best for them. Full vests are cool and all, but take weight into consideration as well. My CIRAS fully loaded with gear and 3L of water weighs in at around 20lbs. Add your AEG, sidearm, and everything else and that's a lot of gear to be lugging around in the heat.
Last edited by Scopedog; January 4th, 2009 at 22:44..