Have you considered the 1D4? It is a beast as well, and would be a great upgrade to your 1Ds. I would put the 1D4 against the old 1Ds any day. It is easily 75-85% the camera the 1DX is, based on personal accounts and having owned the 1D4, at 50% the cost. It gives you a great upgrade in a much shorter period of time, and later you could then change over to the 1DX.
I would dare say that you may never pick up the 60D again, or very seldom if you had the 1D4. It does everything better, has longer battery life, etc, and the only downside is bulk vs portability. It sits right between the FF and crop too, in regards to DOF control and reach.