I voted yes. I'm sorry Camtasia doesn't have a shortcut for you. What they really need is a full featured programmable keyboard shortcut menu. If it's a function, you should be able to assign a key to it. That way everyone has choices.
One thing you might want to consider as a work around is to use the built in Windows "On Screen Keyboard". I just tested it and it seems to work. I click the Shift key there and it remains in the "clicked" state. I'm then able to click and drag the clip to perform the ripple action.
For the On Screen Keyboard, just click the Windows start button and type on screen and it should show up.