CVS has a default template that is used for commit messages. FreeBSD has extended it with several lines of data to allow more precise information to be included in the commit message such as the PR number, by whom it was approved and so on.
The SVN client generates the template locally before commit. We would have to patch the client or have an editor shell script.
Hg runs a command called hgeditor when committing, it is a shell script that be tailored to our needs including template support.
git-commit is just a shell script which could be extended to start the editor with a simple default template
Not Supported (also see monotone:FeatureLogTemplates)
This is not presently supported by Monotone, but would be simple to add - just nobody has gotten around to doing it yet.
It is possible to test the commit message for compliance to rules (see VCSFeatureLogReview), and it would also be possible to implement this using hooks. One suggestion would be to use a hook on other commands (like update) to copy the template to _MTN/log if it is empty.