Like Move proportional tool but for objects. I think I saw somewhere similiar tool (maya?) but couldn't find any video reference.
pretty simple tool, features:
-TAB switches modes translate/rotate/scale (like in tweak tool)
-l/m/r mouse button for t/r/s (like in view space transform tool) .Rot. and scale is temporary, after releasing m/r button, tool switches to translate mode.
-fcurve falloff from Move Proportional tool
-R hotkey for size change (like tweak tool)
-auto key handling for animation
-distance is measured to object's pivot point
-lock transformation to selected objects