Wearable heads-up displays?

[Bruce R. Montague]

Hi... has anyone used FreeBSD with any sort of
generally-available wearable heads-up display? Perhaps   
in conjunction with something along the lines of a
mobile or "wearable" computer?

I'm thinking along the lines of things like these:

  http://www.engadget.com/2004/03/23/the-second-sight-wearable-display/ 

 ("Second Sight M2100")


or what this fellow is doing, at least for the display:

 http://www.openmosixview.com/wearable/

 ("Olympus Eye Trek FMD-200")

Has anyone has done things similar to that mentioned in
the above? (somebody must be buying these):

  "I decided to use video-glasses from Olympus (bought
  from ebay for a few bucks). Those glasses offers
  a high quality video-output with which one actually
  are able to work with a regular X-desktop. I am
  using a "Grandtec hand view" VGA-to-PAL converter
  which displays my Gnome desktop in a 640x480 pixel
  resolution which I set virtual to 1024x768. This
  makes it very comfortable to use with regular
  applications..."


etc..

Any advice? Do these really work? Any downside? Do
your eyes start to hurt after 20 minutes? What if
you wear glasses? If on a vehicle, I imagine the
completely enclosed systems, with no view of the
background, rapidly induce motion sickness.


 - bruce