I guess if you limit the definition of "pipeline" templating to be just whether a system uses a method call to render the template, then Template::Recall is a pipeline system.
But I still feel that the term "reverse callback" is appropriate, because Template::Recall uses template fragments, just as the callback method uses code fragments. It's this opposite that makes me think the term works. Here's how my mind assembles the behavior of these two models.
template ... --> code template --> code template ... etc
code ... --> template code --> template code ... etc
where --> is the callback occurance. The "callback" mechanism is essentially an 'eval' (right?), while the "reverse callback" is basically substitution.
I picture a pipeline system more like
code template ... ... ... ... ... --> ...
where the rendering occurs at one time, e.g. HTML::Template->process() after the the appropriate data structures have been setup.
I'm largely speaking for Template::Recall here, since it takes its name from "reverse callback". I'm not quite sure that I would call all systems that work on template fragments reverse callback. Or "push", for that matter, although both terms work to some degree. "Pipeline" works too, in the narrow definition above, but doesn't provide much of a distinction.
P.S. My Interent is spotty for the next two days, so I'll try and respond, if necessary after that.