I had no idea the extra copy and paste functions existed, and are so powerful!
I understand the method your proposing, however the (CTRL+SHIFT+V)orient and place tool does not take care of variable-length pointer lines.

While thinking about it further I did come up with a work around - using the "line/line" orient tool: Starting with your idea of having a predefined pointer(moved to one side for now) I activate the tool(with options set to: "copy" and stretch") and follow the usual procedure. Stretch ensures the arrow is minimally changed and copy means I can draw many pointer lines after a single selection.
The next improvement will be to find how to pre-load the pointer object automatically, and the start and end points pre-selected for the "line/line" orient tool.

Thanks,
Ambimind