Technically speaking anyone with a modern computer monitor has an HD capable display. Are we assuming every display has a tuner?
If we are counting tuners, then I have more tuners than displays. Including one ATSC HD tuner that can't actually display HD. (WINTV-D)
It's also the case that most digital projectors (XGA) are not true HD displays. It's only when you get to the 1280x720P 16:9 LCD and the WXGA D-ILA projectors that true HD is possible.
Having said that, there is still a pretty big difference between DVD and true HD on a XGA display.