One of these little micro-pumps would be great for a miniature hydraulic robot, with electrical actuation of its actuators. My system is doing that except, I'm making my own electrostatic version, they operate at 10 kilohertz but they only have a micrometre stroke. So if you multiply 0.0001 by 10,000 you get 1 cm a second, of say a radius of a cm^2.
If you use millimetre channels then that could be 100 cm a second, which is more like what you need for a fast little critter.
I bet buying these is alot more cost effective than buying DC motors!!!