Biggest issue would be getting the licensing rights to the video footage I'm guessing. The best option may just be to favourite in IE9 on the phone the NFL website where video highlights are on the web, for watching when mobile....
I know an Aussie Developer that has released this fairly comprehensive NFL 2011/12 Season App:
This app includes the following great features :
- View complete schedule for nominated Team.
- View schedules by date or by team.
- In App Live Scores
- View Online Rosters/Stats/Standings/Odds
- Live Standings (for NFC/AFC/League))
- Browse Latest RSS News Feeds from Major Sites
- Comprehensive Venue Guide/details with Maps
- Preloaded Images/Data minimizes bandwidth.
- Easy to use and Intuative UI
- Autoconverts Match times to Your Local Time.
- Auto Updating Schedule
However I'm guessing the video highlights would be just too damn expensive to license - so THAT App feature would most likely have to come from whoever has the Broadcasting rights....