Feature for level indicators

I would really like to have a level indicator that takes + or - values and fills in either direction from the middle. For example, max 100, min -100, origin 0. So +50 fills from the middle half way to one end, and -50 fills from the middle half way to the other.
This would be real useful for things like rpm (encoder) output, +/- current sensors etc.
Possible different colors for <0 and >0 would be a bonus.
Come to think of it, different colors for different limits would be nice to have in the current level ind.
If you add this I swear I'll buy the full version :-)
Thanks,
Colin