Just received this through the Xbox Live Rewards. Not something I would use so its free to a good home. First to message can have it. I will PM you the code.
Halo: Reach Banshee avatar prop
To redeem your token for your Banshee:
1. Visit https://live.xbox.com/RedeemToken
2. Select "Redeem Code" from the "My Xbox" dropdown
3. Enter this code: