For reliability, get a traditional coil shock. I say coil shock, because I have seen Fox Floats last less than a weekend before they were leaking air from the air spring chamber. Conversely, I have seen them last several seasons in very rugged terrain.
You're kind of asking for two or three different sets of shocks in one package. It won't happen. A happy medium would be a nice set of Elka or Custom Axis dual rate, remote reservoir or piggy back. Compression and rebound adjustment will give you a little more opportunity to change the way the shock performs on different terrain, within reason. Don't expect compression/rebound adjustments to make the shock act/react completely different. Figure on a dampening change +/- 12% lock to lock on either adjustment. Dual rate shocks are recommended on a Banshee, due to the excessive weight on the front of these bikes. Triple rates will not HURT anything, but there is no sense in paying extra for any more than a dual rate. Every shock manufacturer that is not after ever dime in your wallet will agree.
Summary: Dual rate Elka or Axis, Piggyback or Remote Reservoir, Compression/Rebound adjustment.