I've done some googling & can't find anything, so I presume there's not a plugin for this. But here's what I'd love to see.
Ability to set gather rates specific to the tool. Example..
- Stone Pick Default rate
- Metal Pick +50%
- Salvaged pick +125%
- Jackhammer +200%
Not sure if it's possible, but i'd love to see this part of this plugin.