we are looking for a company that configures shoulder mounted lcd
screens that would be used to run commercials at outdoor events. It
would be approx 18" screen mounted above a back pack with a power
supply and PC inside. We have seen these at the US Open and Music
Venues but can't find a manufacturer of a large lcd that can rn off a
battery. The screens are mounted above the persons head as they walk
through the crowd.

General Digital (phone: 1.800.952.2535) makes semi-custom "sunlight
and day light readable" LCD monitors from 6" to 20" and DC-DC
stand-alone power supply with a 4' cable. You'll have to talk to one
of their engineers about modifying the LCD and power supply to a
"shoulder-mount" or...a cheaper alternative comes to mind...why not
put the laptop and the power supplies in one of those hiking backpacks
that have the high profile metal frames and mount your monitor
directly to the frame? (A 4' cable gives you a lot of leeway.) Good
Luck.

A 17" laptop such as the Apple 17" Powerbook or the Toshiba Satellite
P25 might work. The Powerbook can get up to 4 1/2 hours of battery
life if you're not using the DVD drive. The Toshiba is cheaper but
uglier and it only gets about 2 hours.

http://www.apple.com/powerbook/index17.html
http://www.csd.toshiba.com/cgi-bin/tais/pc/pc_cf_prodChassis.jsp?comm=ST&pfam=Satellite&pmod=P25

we were looking at some of those back packs but did not see one with a
large metal frame we could mount a 20" to 24" screen on. Any
ideas,manufacturers? , the back pack would be great for stashing all
the batteries and computer in. We looked at the laptop option as well
and that should work. It is powering the big flat screen we were
cooncerned about.