How do I retrieve an unsaved word file on a mac - using mac office 2011?

I LOVE YOUUUUUUU

First, I'd like to say thanks to Daniel and all of the others on this thread who've contributed. After quite a lot of effort, we were able to successfully recover a lost file. I'd like to share the details because I honestly never expected us to recover it.

My partner had created a new Word document on her Mac and, without realizing it, had continued to make lengthy edits to it for several days without ever saving it once. She then mistakenly closed it without saving it, thinking she was choosing not to save an entirely different file which she no longer needed... When we got started with the process of trying to recover the unsaved file using the various techniques above, things looked grim pretty fast. We couldn't find any temp files of any kind that Word might have created. My partner's copy of Word was indeed set to autosave every 10 minutes, but because the document had never been saved, there was no apparent work file to recover from anywhere - consistent with Dan's guidance above.

Since the document would take days to recreate from scratch, we decided to by one of the file recovery utilities at Dan's link above. In our case we chose Data Rescue 3. Though I suppose others might have worked also, I can't recommend Data Rescue 3 highly enough. I've used other recovery utilities before on Windows Machines, and Data Rescue 3 was by far the easiest and safest to use that I've encountered. Anyway...

It did the job. Data Rescue 3 was somehow able to take disk contents hidden from the view of the Finder in OSX Mavericks (even with the settings to show hidden files enabled) and reconstruct several versions of the document in various stages of completion. It was as though it was finding disk contents which represented some sort of temporary disk cache of the Word document and reconstructing a Word file from them - perhaps from a Virtual Memory file as Dan hints above. Data Rescue 3 referred to the Word files it "found" as "reconstructed files," so perhaps that's what happened.

Speculation aside, a few tips here for anyone that wants to try using Data Rescue 3 for a similar salvage project:

1. Stop using the computer on which the file was lost as soon as you determine that you need a file recovery utility. The longer the computer is in use, the more likely it is that any file which might serve to help you reconstruct the document will get written over, rendering your efforts hopeless.
2. Budget a lot of time. Many, many hours will elapse from the time you start the recovery process with the utility until you have data in which to search for your potentially recovered document. Once you begin the file recovery process, your computer may be unavailable for any other purpose for as long as a day or two. In our case, something like 18-20 hours were required for the files to be recovered and written to disk.
3. Speaking of disk, you'll need a rather large external hard drive for this process. My partner's MacBook Air had only 256GB of storage, but the recovered files consumed just under 2TB! I fully expected the recovered files to take more than 256GB, but I would never have guessed that they would have required nearly 8 times the total storage space of the hard drive on which the document was lost. You'll also need an external DVD drive (I used my USB Superdrive) from which to boot the Mac using Data Rescue's boot DVD. You can order the boot DVD online, or make one yourself with a download after purchasing Data Rescue 3. Having my MacBook Air handy was also invaluable, as I was able to do lots of things to speed the process along which would have been slower and more risky had we used her Mac to do them.
4. Data Rescue 3 reconstructed something like 4,000 Word Documents and placed them in a folder named "Office". I copied that folder to my computer's boot drive and then used Spotlight to search for strings of text in those documents. I used phrases that my partner believed were probably unique to her document. Without that information, I doubt we could have found her document so quickly once the reconstructed files were available. As it was, it took me only a couple of minutes to narrow down the list of documents to a set of four which matched. The lengthiest of them was very nearly the full contents of the document's last form before she accidentally closed it without saving.

Anyway, thanks again to Dan and everyone. Whether Word on the Mac intends to or not, it appears that traces of unsaved documents will at least sometimes be written to disk in clear enough form that a file recovery utility can reconstruct them into a readable document. In other words, even if you never saved the file at all, there really may be hope worth holding out for.

Best of Luck to all in this situation.