I haven't tried it out yet (I'm at work), but they said yes you CAN use flash media to use for movies and pics. He did say you could use an external HD as long as it is formatted to FAT32, however he sad he believes there is a limitation to the size of the drive, but he didn't know what the limit was. You might need to give them a call for more specifics.
I haven't pulled mine out of the box yet, but I did check one out at their facility. About the same size as the 970, but looks really nice in black. Will have pics and info once I fire it up and try it out tonight.