Pilfering's a great idea :)
Coincidently, now that I've played with the form builder a bit, I'd like to have higher-level elements there, too. We don't want to build something overly complex or ornate, but we do whatever we can to make page building as painless as possible.
And extending tags on the template side, and form widgets on the input side, seems like a logical way to do this if we do so in a somewhat *disciplined* way.
Hopefully as soon as we get this release out the door we can form subgroups of interested folks to make recommendations for improvements in various parts of the toolkit, with the goal of building a roadmap for our second release cycle.
Some standard CSS classes are a good idea, too, I think.
I'd just like to see us proceed in a somewhat orderly fashion rather than add specifics in an ad hoc manner.