Ok, it took me a while to get around to it, but I made an export filter for Scrivener to create DOC files in the Smashwords format. I just uploaded a story I had laying around, which was only two pages and a single "chapter", so it would be nice if other people tried the export format for larger texts to see how that works.
You can see the one I uploaded here:
https://www.smashwords.com/books/view/5399
The PDF looks good, it didn't keep the cover image, though. The LRF did some weird spacing stuff, but centered the text properly. The EPUB format looks great, but it justifies everything to the left, and sticks the cover image way up at the top of the page.
Let me know how it works for you. You need to put the attached xml file in your local (not system) Library/Application Support/Scrivener/ExportSettings/ folder, and Load it when you are in the export panel.
Cheers!