I've just found this intriguing new monitor online:http://www.carcomputer.co.uk/virtuemart/monitors/usb-monitors/lilliput-um73d-7-3d-monitor-non-touch-screen
It's a bit too expensive for the size and resolution, but I like the fact that it doesn't require a separate power source; it could be connected to a laptop or even a netbook as a truly portable 3D monitor.
Going by the specifications, I would guess it uses the same panel as this digital picture frame:http://www.3dinlife.com/english/Products/SDP918.html
If they can produce a monitor like this with a slightly higher resolution it would make a very nice product.
There seems to be someone selling them on Ebay