I've made an hybrid with the gem vu-meter and the v-slider mouse bindings,
 by adding a background image it looks like a decent little mixer track

<img src="http://megalego.free.fr/pd/Gem/HA_Mixer/gem_fader.jpg" />

http://megalego.free.fr/pd/Gem/HA_Mixer/HA_fader.zip

now it just need to display correct db values

the vu-meter answers perfectly, the signal peaks when the it reaches red rectangle

thanks for sharing