<p>When commiting to SVN I can add a top level commit message to detail what is being committed, but I would ideally like  a means to comment on the individual files and what has changed within them. I have seen something similar in previous employment, but this was using CVS (and I can't recall whether this was achieved with a home brew script to produce the skeleton file) </p>

<p>I have had a look at changelists but again I don't think (although i am willing to be proved wrong) that this gives the kind of granularity as outlined below.</p>

<p>Ideally I am looking for something along the lines of:</p>

<p>Foo.vb</p>

<blockquote>
  <ul>
  <li>Added new function bar</li>
  </ul>
</blockquote>

<p>Bar.vb</p>

<blockquote>
  <ul>
  <li>Removed function foo </li>
  <li>Added functionality in xyz to do abc
  +/- Modified function to log error</li>
  </ul>
</blockquote>

I would just do this in the individual commit message.
TortoiseSVN
has filename autocompletion so that greatly aids in this.
Another thing you could do is svn st before you commit and copy/paste the filenames into your commit message.
Oh, and be sure to strongly question the value of this. I know some OSS projects (linux?) require this sort of fidelity, but for many projects this is just noise. Diff can tell you much more than this, and more accurately.
One other thing you may want to consider is using
Git
. Git allows you to commit locally, in smaller steps. You then push to the master server all of your commits individually or squashed into a single commit w/ all the commit messages in a single message. That was a way simplified explanation, but it probably is worth checking out.