Here's a link to numerous technical articles that can present the challenges of what you suggest. Choose your poison but it's not as simple as one may think.Sorry if this is a novice question, but simple as it is no friends have been able to answer. Since we made the switch to widescreen mostly flat panels in the past 10 years, its seems for every 1.85:1 movie (that fills entire screen) there are twenty 2.35:1. Now I'm not complaining, just curious....figured since all TVs made the move to go widescreen to get rid of black bars that they'd want picture full in, if so why aren't the TV manufacturer standards setting them up for 2.35 to be (is "native" the right term)?
FILM FORMATS/Aspect Ratio's: http://en.wikipedia.org/wiki/Aspect_ratio_(image)
A summary review of this material demo's the challenge as far beyond any close to simple especially when standards are so diverse globally and the TV market is limited by those regional differences also. There were discussions about ten years ago by Sony that they were developing an SXRD that could adjust the pixels displayed to adjust to different formats but then they killed off SXRD tech shortly after.
Reading these and other spec's that impact such a capability may provide 21:9 wide screen but may adversely impact other formats and sometimes it's been done but often on a panel that can cost around a $100K+. I believe Samsung and others has demo'd them at CES.