Dodge,
You might want to edit your post to add a question mark to to change it to: "942 with external hard disk?" to avoid being flamed. This way people know you are asking a question and not telling us that it is possible.
To answer your question, it's been said on a Tech Chat that the USB port would be made available to hook up a USB camera or storage device to upload your pictures or music to the hard-drive for your listening or viewing pleasure. They also mentioned they are looking into an external hard-drive solution, but just because it was mentioned, it doesn't mean that we will definitely see it. For now you have to go on the assumption that an external hard-drive will not be made available and make your purchase decision on that. Hopefully, they won't repeat the Dishwire fiasco and mention something that later gets scrapped.
As far as issues with the 942 there are some, but not nearly as many as I had on my 921. I still don't have my OTA guide data for one of my OTA channels, which could be due to the way that station handles its PSIP info. Also the guide gets cut off on the bottom of my TV screen. This is because of my TV's over-scan and the fact that the 921 doesn't have an adjustment to the size or location of the image. If you read more or do a search, you will find some more problems, but the 942 has been fairly stable and very reliable for me. Good luck.