I understand that 'ideally' no one is watching their tests as they run, but unfortunately that is what I have to do with my company. Our site performance can get slower/faster as the day goes by, so ...
Have you tried using the "WaitAlias" or other similar functions? What those methods do is allow you to set a Maximum wait time for an object to become available. If the object is available sooner, it will return sooner. This might be better than hard-coded wait times.
Suffice it to say, it would be cool to have some way of saying "Skip this test" but I'm not sure how practical that will be. It would have to be something implemented in the TestItems or in Keyword Testing to indicate to skip a test after a particular time out or prompt an attended user to do so.