I think some reservists do qualify to stay at Shades of Green. Their website www.shadesofgreen.org states that members of reserve components(Ready reserve and National Guard, and reservists in training) are eligible. Shades of Green does not just give a military discount, they are actually owned by MWR. They are closed for remodeling until late 2003 so anyone making reservations are being put at the Contemporary. For more information you can check out their website or call them to see if you are eligible to stay there. As far as I know, this is the only onsite hotel that gives any kind of military discount. You can also get discounted park tickets through Shades of Green.
My DH is in the Nat'l Guard reserves and you do qualify to stay at the Shades of Green. We just stayed for 9 nights for $650- a BARGAIN! (this was at the Contemporary) Just go to www.shadesofgreen.org and look up the info- your room rate is based on your pay grade. As far as other Disney properties go, I don't think they do offer a military discount, but if you book right now with Shades of Green, they are putting people up in the Contemporary through November/early Dec. I think if the time you want is booked, you can ask for overflow rates at other resorts- it is more expensive than the basic SoG rate, but still a good deal.