Aw hell no. $400? Madness.
To be clear, what I meant was the typical widescreen DVD-only monitors that go in car AV systems, and have the bare minimum vertical pixel count for NTSC, and AV inputs only - those should be avoided.
There are decent 8"-10" 4:3 aspect LCDs available, with VGA in, and at least 640x480 pixels, around the $200+/-$50 mark.
But I still say the most cost effective will be a MiniITX with LVDS and a bare panel.
/edit/ The Intel Jetway J9F2 Extreme - socketed CPUs, takes Core2Duos, has LVDS video. Admittedly not as cheap as the Atom boards, but holy spaghetti monster, that's a lot of expandability in a small board.