/clone ... replace move should work like /clone ... replace force, and never fail when source and destination overlap. However it does in some cases.
Example that fails:
/clone ~-5 ~-5 ~-5 ~5 ~5 ~5 ~-5 ~-4 ~-5 replace moveExample that succeeds:
/clone ~ ~1 ~ ~ ~3 ~ ~ ~2 ~ replace moveIn both of these cases, the source and destination overlap. However in the first case, the command fails. Both commands should succeed.
Upon my testing in release 1.8, I found the following:
8 blocks in a 2x2x2 area works fine.
12 blocks a 2x2x3 area, assuming any pattern using all 3 axes, fails.
Past experience had me needing to either move one layer at a time, or to a temporary spot before to move it to the proper location.