Forms - Collapsible Category Section

Hi,

I've got a form with similar requirements as those described by this person. Understand Brenden's recommendation - ie, to apply relevant visibility to individual fields (and I'm already doing that with a lot of fields in this very extensive form) - but that's not what I'm trying to do.

Because the form is very large - in this instance more than 100 fields - for useability it needs to have relevant headings applied to sections of the form. Form categories are good for this and if the default layout is suitable it's a perfect solution, particularly as you can specify categories to be collapsible as well as collapsed by default.

BUT ...

The problem is the default layout is in <table> layout, making it terrible for mobile display!

So:

1. Has version 9 changed in some way to allow me to include Categories in a form's custom layout? If so, how do I do it? I can't see the Category fields listed anywhere.
2. If not, is there a way to remove the default <table> layout of form so that I can apply css classes for mobile-friendly layout?

It's the ability to setup "Sections" of the form in categories, together with the collapsibility of the Categories and flow-style layout that is important. The people using these forms will be using their mobile phones in the field. The default <table> layout is completely inappropriate.

Thanks for your ideas!