You need the mq extension.
The equivalent of -
$ git rebase -i HEAD~2
In Hg would look like -
$ hg qimport -g -r -2:-1 $ hg qpop now at: 2146.diff $ hg qfold 2147.diff $ hg qrefresh -m 'new log message' $ hg qfinish --all
The '-g' flag is a must if you have any binary diffs.
Of course this doesn't help you with reordering commits... :/