eBay has a bunch of them that were designed for automotive use. You may find something there.

Parts Express has a 4" LCD module for $98.00.
They also have a 6" module for $168.00 and a 7" 16x9 Monitor for $159.80.

John

I was really thinking of getting one of these little monitors myself. It'd be nice for on camera viewing as well. Also it'd be handy to have an actual 16x9 display.

But the problem I thought of is how would you power it if you're walking around ? Do any of these monitors have batteries or are they all AC powered ???

Stan . .I was rummaging around for this one for you .. .

http://www.studio1productions.com/lcd_monitor.htm

I've got a monitor with which I use a lead acid battery - dirt cheap and totally reliable. I built a container for it, slapped on some dual pole isolators and some car cigarette plugs - total? About 30USD. Bought a black travel bag, sling it over my shoulder and away I go! It takes 3 hours to charge and lasts - well I've never found out! At least 4 hours I guess. Cheaper and I've been told safer than a Lith Ion that can go south if you totally discharge them. I can trickle charge this battery as it is one of those "safety/security" light batteries .. yeah?

The link I gave shows where I started with an idea. Started to understand the issues around using lith ion and kinda slid away and towards lead acid. .. Anyways, your call! Lith ion ARE lighter - but may not have the high demand for the period. Lead acid do, and once encased within a hard plastic case are robust enough for my treatment.

Grazie

I was really thinking of getting one of these little monitors myself. It'd be nice for on camera viewing as well. Also it'd be handy to have an actual 16x9 display.

But the problem I thought of is how would you power it if you're walking around ? Do any of these monitors have batteries or are they all AC powered ???
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They are mostly designed for automotive applications and thus are designed to operate on 12V DC. For AC operation they operate on a DC 12V adapter (wall wart). You would need a 12V DC battery pack for portable use. Some very few are designed to work off the camera battery pack but that would eat up the power really fast so I wouldn't recommend one (overpriced anyway).

You could make one out of ten 1.2 v rechargeable cells if you want to. Larger cells would be better but bulky. AA would work.
There are lots of battery pack projects on the internet if you have some soldering skills.

Ipod battery pack projects would also work.

John

http://www.trewaudio.com/esale/20051014/videoassist_details.htm

An oft overlooked, and simple, thing you can get is a portable DVD player. For around 100 bucks you can get a 16:9 one with a 7.5 - 8.5 inch screen. Make sure it has video (A/V) inputs and you are getting the "full" package. Some of them are sold for car use only and you need to get the battery seperate.