Hmm. Can you ask less generic question, please? :) What exactly is 'less generic' in my solution?
'Tag names' and attached 'result convertion' action can be made configurable as I show in previous post without introducing significant complexity, if any. This way I'll have things like "<% ... |blog %>":
$t->text('<%', '|blog %>', \&MyBlog);
'include template' feature can be developed in many different ways, from simple including header/footer templates (which will in most case doesn't have any perl code at all, or will use few local()'ized global variables) to something OO-like which surely may be very complex.