Stuff like this, and potentially this make me very eager to get a copy of CaScadeS II. Those are some very welcome features, that would save a ton of time. Especially if they can be done within Firefox.
One of the biggest caveats of CSS is that it’s such a pain to develop with. A good development tool doesn’t fix the problems CSS, nor the implementations (or the differences in implementations), but does make it a little easier. Now if it had some magical way of helping you with layout (something like layout-o-matic but better), it would be a WMD in the CSS arena. Something to help create various popular CSS layouts,
[fluid/fixed] layouts, with options for header, footer. Likely wouldn’t be to hard. What would be make it tough is making it flexible, while keeping a user interface that someone without a PhD. could understand.
For those wondering, I have tried TopStyle, and yes, it’s not a bad CSS editor, but I don’t think it really saves me any time, your mileage may vary. Though I haven’t tried the pro version.