Revolution builds a unique internal bypass shock that is adjustable from the outside.
To the best of our knowledge this is the only shock of it's kind. The bypass operation happens on the inside of the shock body instead of the outside like all traditional style bypass shocks.
At the top of the shock body a billet aluminum cap includes adjusters that control flow of each bypass tube. On the 4.0 series you get 4 compression stages and 2 rebound stages.
The killer part is all the "bypassing" of shock oil happens inside the body of the shock so you don't have to listen to the typical "tapping" sound commonly associated with bypass shocks. They also package into tight spaces much easier.
The downfall: These are a super high end race shock and are priced accordingly.
If your in the market for a high-end set of shocks for your rig give Revolution a look.
They may have exactly what you need.