Integrating Resizable Body with Private messages module

Would be great to also enable this also for the Contact forms through which people send e-mails to administrators and other registered users.

Update:
I've tested the Textarea Expander module http://drupal.org/project/textarea_expander
It works okey for the Private Message fields and Contact forms, but there is none of that lovely "Autoresize- with animation" effect.
So, why not merge these 2 projects into one? or, alternatively, you could take the code from that module so that it works for ALL textareas, like Private Messages, Contact forms etc. It would be nice to have a settings page with a checkbox option "Make all textareas resizable by default, unless specified otherwise in particular content settings".

Update:
I've spoken to the people at Private Message module

they said:

the body field is called $form['privatemsg']['body'] (note that the ['privatemsg'] part will soon be removed in the 2.x-branch) and the form is called privatemsg_new, see also http://blog.worldempire.ch/api/function/privatemsg_new/1

I tried to tweak the Resizable Body code, but not being a coder, I couldn't get it to work.
(frankly I'd like to see ALL textarea forms in my Drupal installation resizable by default)

Is anyone else interested in a Resizable Body for Private Messages functionality? Any ideas on how to get this to work?