It was an issue of converting .swf files or getting ahold of original, uncompressed files and my client finally got me a copy of the original. I ended up finishing the project in iMovie due to the pressures of a deadline and the steep curve of learning a new video editor (I already knew iMovie).
Still, I see a combination of Final Cut Pro and Vegas filling my future needs. Any information I can get about FCP right now is very welcome indeed.
I recall that about a month ago you were asking about Final Cut being able to intermingle files among different versions. I found an article that might answer that if you haven't already.
Sorry if this has already been confirmed.