I thought about the 24-105L,  that is the one I miss on the small three! (I have the 17-40 F4L and SSW IS)
but the focal length is a little too long if it is on a crop factor body.  and the price is too high,  (add US $150) and you can get a 24-70 F2.8L (either new or used).
So unless I decide to get a FF,  I probably won't get it!