Dafni, the Nomadio sensor can give you voltage readings and temp and can give you beeps and vibrations on the transmitter for pre-set high temps or presumably low voltage aswell.I think it comes complete with sensors and it sounds perfect for brushless.
Maybe could be used instead of LVC for Li-po.
There's a little video explaining it here
http://www.rcuniverse.com/magazine/a...article_id=525
If Batfish reckons it's worth it I might get one.