Something I am missing from the rebase command is 'rebase amend'. The
idea is that this should enable me to amend a patch even though other
patches depend on it. It should work similar to 'rebase pull', i.e.
suspend (only) the patches that depend on the one I select for amending.

Very useful if you record a number of small changes in sequence and
afterwards find you made a small mistake 5 patches ago, want to amend
it, and then find that you can't because some of the others depend on
it. Could of course suspend them all but it would be nice if darcs could
help you by finding out which need to be suspended and which not.