Hi Paul,
Thanks for responding to such an old thread! I think in the months since I originally posed the question I was able to figure it out... if you use the embed code for the form and modify it with this: http://developers.marketo.com/documentation/websites/forms-2-0/ -- you can overwrite redirect settings without having to use a landing page. Likewise, you can then use the URL for where the form is going to sit in a trigger campaign, which could then send an email based on that page, set data values, etc.