I've been researching various document viewers for possible implementation on Firenest, and I was quite impressed with Scribd's iPaper interface. Unfortunately I wasn't able to find any documentation on SSL implementation through their API, and had actually quite convinced myself that such support didn't exist. Fortunately Jared at Scribd was able to correct me on this and point me to the following link, which I'm hoping to make easier for others who are in a similar situation to find:
Scribd Does in Fact Support SSL!
I will likely be making a more detailed post about the various findings I've discovered researching and playing with the currently available embeddable document viewers I was able to find, so stay tuned for that.