using view helpers in JavaScript templates

I'd like to use ERB in my JS templates. Sometimes I want <%= image_tag
%>, other times I might want something more serious/non-assety like <
%= form_for %>. (There was an issue for Sprockets to allow for
ActionView to be used in the asset pipeline so that that could work:
https://github.com/sstephenson/sprockets/issues/218, but it turns out
it's not so simple.)

I guess there are a few ways that I could do this, so I'm looking for
a best practice. How do you handle view helpers, like form_for? Do you
render your template within the view, or do you just use old school
pure html, or are there any bridge approaches?

Right now we're trying out codebrew's backbone-rails gem, but we
definitely need to find a migration path for the extensive system of
view helpers both in Rails and in our own project that we'd like to
reference.