Look also for 2007 Haro Mary bikes. Great value and they should be right around 800 now with discs. Other models to keep an eye out for would be the Redline XXiX (nonsuspension corrected if that floats your boat), and if you don't mind using V-brakes exclusively the GT Peace is a nice 29er SS. Might be hard, but it might be worth it to keep an eye out for 2007 Jamis exiles as well.

Then again - the Monocog ain't too bad either.