Looking through the source of HTML::Template, I see that you can pass it a filehandle for the input template. So as an intermediate stopgap, you could open / binmode the template file yourself and then let HTML::Template handle it. Template::Simple seems to mostly render templates from scalars or scalar refs, so there the same technique could apply. Petal's templates are XML and it claims to handle (eq let you specify) the encoding.

But yes, it would be convenient to have this on a "template checklist", which compares the features resp. solutions the templating systems provide.