Um, the DATA method is what we are talking about!
You just put your template in the DATA section of your
Perl script. I use this all the time for simple CGI scripts
and examples i post here at the Monastery - but for anything
serious, i use another file for the template. As for your
overkill problem, the more you use HTML::Template the
less the overkill seems to be a problem.
If you read the original question again, you will see what the DATA method that I am talking about refers to. It is a method for adding a __DATA__ section to your perl code, where perl will automatically provide this data in the file handle DATA. The above question gives an example of how to use this using HTML::Template.
For more info, check out perldoc SelfLoader for some more info on __DATA__.