Dave,
First, let me make sure that this is clear. I am not part of Marketo. I am also a client. I felt I should clarify that since you said "Do you guys understand what we are asking?".
Now, I have been able to use CSS media queries to completely manipulate the way that the Marketo forms are rendered. You are not really locked in to their rendering. Granted, you can not do everything you might want, but most of the manipulation you need for the smallest viewports (mobile) is possible.
While we have not gone live with a major roll out of this capability, I have a small set of pages running as a pilot that respond to the different devices screen/viewport area.
The following page is in our Marketo QA instance and can go away at any time, but if you open it in different devices, or even re-size your browser screen, you can have an idea of the basic implementation that I did for this round.
I would ask from you (all) the favor of please not sharing this URL outside the Marketo community since this is NOT a production instance and please also don't submit the form:
http://test.deliver.citrix.com/OptimizedLightMaster.html It is also a work in progress.
I did not use any special libraries like Bootstrap or anything like that. Only pure hand-coded CSS which you can see here:
http://test.deliver.citrix.com/rs/citrixqa/images/responsive_v2.cssThere is one other CSS on the page which is separate for now that is a boilerplate responsive CSS generated by Adobe's reflow. However, it has nothing to do with the form, only with the template look and feel. I also modified it to be on-par with my particular goals for this test.
I hope this helps you somehow see what I meant on my previous comments.
Thank you,
Rafael