You might've picked up on this from The Perl Cookbook. It's recipie 1.16 of the second edition, and there's a few other embellishments there in the discussion section that you might be interested in.

Myself, I recommend just giving up. This a piece of fugliness in perl syntax, and we just need to live with the pain (until perl 6 arrives).

It looks like you're already handling the problem the way I do: I put all my heredocs in wrapper subs that do nothing but return the string... and all of those subs get segregated at the bottom of the file under a comment that says ### heredoc ghetto.