We were introduced to Acros' hydraulically-activated derailleur system for mountain bikes at a presentation in Park City, Utah. A short demo ride was interesting to say the least and we looked forward to getting some serious saddle time on the product. Unfortunately, two years later we have yet to find the system on a bike and we have not seen one in a bike shop. That's too bad, because taking a look back, it wasn't a stretch to see how this could possible have the same affect that hydraulics had on mountain bike brakes. Here is what we saw in 2010.
A single hose controlled both the up and down shifts. You can read more at Acros' website.
The paddle shifter was the coolest feature of the system. It rivaled electronic shifting in smoothness.