hardcoding mtimes for stories in their metadata section

Hi all,
is it possible to hardcode the mtime for a story in its metadata
section?
I.e. something like:

$ cat entries/post.txt
Title of the post
# mtime 2010-10-30 12:00:00
hello, (..)


I think these plugins are not appropriate for me: 
- "wrapper scripts" that change the mtime back to what
it was before editing (not very robust if you work on multiple systems)
- plugins who cache the mtime (I want to dictate what the mtime must
be, which is more robust)
- pyfilenamemtime, the plugin who stores the mtime as part of the
  filename is pretty close, but makes filenames messy, and I don't want
  to rename the file in my vcs just to change the date
- the w3cdate plugin is also interesting, it seems to be close to what I
  want, but it creates a new variable instead of updating the mtime.
  What's the point of that?

I think I will write a fork of the pyfilenamemtime plugin which uses
the metadata section instead of the filename.
Or am I missing something?

Dieter

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