Right. I've attached a patch to the ticket Willr raised, it's written against the trunk code so you'll need that too.
I've got a cold at the moment so would really appreciate another pair of eyes on it, make sure I haven't done anything really stupid!
This patch allows adding custom css classes to individual User Defined Form fields from within the CMS interface for complete control of form layouts
- - add a css class to individual form fields, headings and html blocks
- - predefine which classes a CMS user can select with a drop-down list
- - predefine classes available for all field types and type specific at the same time
- - optionally add user friendly descriptions for the css classes
- - power user mode - text entry of multiple classes
- - ability to disable the feature