I've been experimenting with label/form pairs laid out side by side
using float as well.
Here's the page I've been working on: http://ironandbass.com/SCFCfind
After your post, I tried it with fieldset:
The relevant CSS is in the page source.
Is this what you mean? I don't know how many browsers it works in, but
it seems to work all right in Windows IE6, Mozilla and Opera.
I'd like to find the most reliable way to produce this effect, too...