I just registered here and have not read all the back posts on this one but  a unit that is used
on experimental helicopters with some success is microvib.  See www.dssmicro.com
I don't have pricing info but considerably less than certified units.
Regards..........Jim. 

 

Hi Jim,

 

That's the Dynamic Solutions Systems place that I mentioned.  I had meant to paste in a link but forgot.  They're up to rev II on the MicroVib unit now, and I have an email into them as well.  

 

Rusty (really irritated with sites that don't list prices)