No way to keep the command active, unfortunately. However, if the point about which you want to rotate is a common highlight point when the object is selected (e.g. end points or mid point on a line, center point or quadrants on a circle, etc.) then a fast way to rotate is:
1. Select the object
2. Select the highlighted point about which to rotate
3. Tap the space bar twice, which activates the ROTATE command
For me, this is a fast way to initiate the rotate command. In fact, a little experimentation will show that after following maneuvers 1 and 2 above, tapping the space bar cycles through the MOVE, ROTATE, SCALE, and MIRROR commands, in that order. See if that helps at all.
