Efficient way to check for the changeset of last changes of some file(s)?

[Marcin Kasperski]

Problem: for a couple of files I would like to know in which 
changeset they were last changed (for every file separately).

At the moment it seems to me it can only be found via "hg log", 
but then either one must use "hg log -l 1" for every file 
separately, or call "hg log -v" and parse it carefully analysing 
files: lines. Not very pleasant and not very efficient.

The command of my dreams would be sth like

hg status --all --show-revs

returning sth like

M file1.txt  6:6722a68b6f82
C file2.txt  6:6722a68b6f82
C file3.txt 3:a02895266773
? file4.txt
M file5.txt 5:4f3d1e045daf


PS Background (in case somebody is interested): I need to perform 
some calculations for every changed file, saving info which file 
was already handled in which version in terms of changesets 
seems more solid than using mtime-s.