Performing ActionMailer deliver_* methods for a new Model?

I'm thinking of implementing something like how ActionMailer does their dynamic deliver_* methods for this opensource rails messaging plugin I'm currently working on, but I'm not sure how should I go around working it.

I'm thinking of doing an easy-to-configure HTML templating system that would allow users to customize the output of commonly sent out messages.

But what do you think? Is it even necessary? Or am I adding code bloat.