I\'m trying to use the modals within Twitter Bootstrap to implement a contact form.
Ideally I would like the first two fieldsets to align next to each other and the
Here is a solution only using Twitter Bootstrap 3 classes - namely row, col-sm-6 and clearfix:
HTML
...
First column with fieldset
Second column with fieldset
Row that expands the whole width of modal – text area and submit button
...
Added borders to the columns for viewability below. Note that there is also default Bootstrap padding around the tag, not bordered below.
Rendered preview

If you want to look at how to structure the title or footer of the modal (before/after the ellipses in the above example), you can look at the layout of Bootstrap modals here.