GNome Out Of Mana
Shows a simple bar, which displays the guessed time until out of mana.
There are currently two strategies for estimation, just test which one suits you more. (Suggestions would be great.)
The slash command is /gnoom or /go.
Please note, that the comment sections are not approtiate for bug reports or feature request. The tracker is there for a reason.
Version 2.1 of this is in the public domain. If anyone wants to enhance this, please contact me.