My vote is no right now, because they market this adapter as part of the "Camera Connection Kit". So it doesn't really make sense marketing wise for Apple to market it as such and then turn right around and say "Oh, BTW, it also allows you to open other files types too."
BUT, now that I think of how it works....
Let's say for instance my camera has an SD card in it to store photos. And I have the USB adapter and hook my camera up to the iPad.... The iPad almost certainly has to have a USB controller to be able to see the image files on the external storage device right? So, I could store word docs and such on the SD card as well... The iPad probably wont display them as viewable... but the underlying ability is certainly there. It sounds like its just a matter of Apple coding the OS to only look for certain file types (JPG, PNG, BMP, etc). Who knows. We will see what the iPad actually does once we get our hands on the adapters... whether it just ignores file types it doesnt recognize, or whether it can only read certain file systems or what.