Well, while there might be scripts helping with that, there are at least workarounds:
you can rotate with numerical input, in this example hitting R,-30,RETURN. You can switch on Edge Info >> Face Angle to see what you are doing. And you can rotate around the 3D cursor so you can decide where your center of rotation is (.,, switches back).
An even newer solution would be to select the center vertex last with a shift-RMB and then switch to 'Active Element' as pivot point ALT.). Then you don't even need the 3D cursor for that.
If you need reusable functionality, you can consider using hooks or even armatures to control parts of the mesh from outside.