Kill'em All V1.0
This is an addon for grinding mobs. It will tell you the number of mobs you have to grind in order to level, based on the last 5 or 6 you've killed. Displays status in the chat frame, interaction is via slash commands as follows:
/killemall help or /killemall - Displays a help message
/killemall on - Turns on Kill'em All chatter
/killemall off - Turns off Kill'em All chatter
/killemall reset - Resets data. This is recommended when you start grinding, to eliminate crazy numbers due to quest turn ins. Only 5 or 6 data points are stored at a time, so this is not strictly necessary.
Note: this does not account for change in rested status. If anyone is actually interested in this addon, I'll add that to it as well, no problem. Feel free to put any feature requests in comments here.
It can give you an estimate after only 1 kill, and it will average out the past few kills for a more regular estimate. It should be smart about when you gain a level and give you a realistic value, but it'll be a little low.