I would not Leave out the used market when it comes to buying a transmitter. I also wouldnt buy into the whole 2.4 is the only way to go thing. We flew 72mhz for years and years just fine, and I still do. You can find a once very expensive radio and receiver setup on 72 now for very cheap. Alot of sailplane guys used to fly 50 mhz as well. If you check out the buy/sell section you can find some great deals on good equipment, a real quick sheach found this one which has a sailplane mode and is more than capable of doing everything you could ever need.
http://www.rcuniverse.com/market/item.cfm?itemId=855961