I haven't seen much on the portable options to expand on built in screen realestate, so here is a quick run down of what I've found out. For the most part these are better for multi-tasking than to use as a monitor for watching movies on (though with a powerful computer it should play video quite well, though not as well as a standard VGA/ HDMI/ Displayport screen could, or as well as an expensive home theater projector). The main reason to get one of these over something else is the cheaper cost and/ or the simple fact these are actually portable meaning you can pack it in your bag with your computer with minimal bulk and weight increase. Onto the options: -Pico/ portable projectors will have limited brightness (an issue when used in a room with ambient lighting, darker rooms are not an issue) but the 'screen size' depends on the size of your wall/ desk or any flat surface and the capability of the projector, most use a pretty bright LED source for light but the rest of the system is basically a shrunk down version of whats found in full sized DLP projectors. Because of issues with low brightness, the pixel walk/ screen door effect common in projectors, very pronounced pixels, and need for a decent sized flat surface (also means others around you see clearly what you are seeing), especially with the cost to performance ratio these are not the greatest options for most people. *one of the cooler things I've seen done with these is using them with a Wacom Intuos as the projector back-drop so it is like a cintiq of sorts; and the ones used in conjunction with webcams and some recognition software to read certain things the webcam sees as key presses or mouse movements. Though they seem to be more parlor tricks than they are usable* -USB monitors; these connect to a windows/ mac (sometimes Linux) computer with a USB port or two, the computer needs to be powerful if doing faster moving things or watching videos (the devices are typically using Display Link chips so the driver processes data on the CPU and GPU then compresses it and sends it over the USB cable where the receiving chip basically decompresses it and displays it. For video playback Displaylink recommends a computer with a WEI for CPU and both GPU scores above 3.0). New USB 3.0 capable ones are on their way meaning better/ smoother performance and probably higher resolutions. Because of the nature of the data being compressed and sent over USB 2.0 there is some data that is sacrificed, namely the color depth; to the point that gradients do not display smoothly, but colors seem to be fine otherwise. There is supposed to be a max of 6 DisplayLink devices on one computer so you could really go hog wild with a portable multi-monitor setup if you have enough ports and CPU/ GPU power -portable 'micro connection' monitors are basically regular monitors shrunk down in size, with standard port types (typically HDMI, Displayport, or DVI, maybe VGA, usually using a proprietary connection/ cable) -There are of course the standard USB video docks that connect through USB 2.0/3.0 and have a displaylink chip inside and some kind of video output; these obviously need a device with a video input corresponding to that output (a monitor, or a projector) -The older cintiqs to an extent... too bulky and awkward to be considered portable. *You will probably want to use a mouse and keyboard setup with these if at all possible, of course if you have a Tablet PC you shouldn't have any trouble with setting it up so the external screen is the main and only screen so the pen & touch digitizer are mappedd to the external making it into a portable Intuos & monitor like setup. If you have a computer and a display device with the same aspect ratio and resolution then you may want to set it to mirror mode* Pico Projectors - The AAXA M1 & M2 are some of the better featured mid sized portables (decent brightness, XGA or near XGA resolution, assortment of inputs, though larger than the others) ACER X1161P & X1261P are among the decent featured large portable units; then there are the palm sized ones some of which have batteries that can last 1hr+, or SD card slots, USB only connection or VGA/ HDMI/ others through a proprietary connector, different native resolutions, brightnesses... there are many features that may seem overwhelming but it seems for the most part that the most important are resolution, brightness, and connection type, the rest don't usually matter as much (though sometimes a palm sized unit is the only option). USB Screens - Some of the models to look at for large-ish screens: Toshiba PA3923U-2LC3 - 14" 1366x768 13.4 x 9.4 x 0.6 2.8 lbs [with cover?] 220nits with optional AC adapter (on USB only there are two brightness settings, without AC it is supposed to be dimmer) 5W max around $180 Lenovo LT1421 - 14" 1366x768 13.2" x 8.59" x 0.85" 1.9lbs for monitor & 2.31lbs with cover 220nits on USB (16 brightness settings, rocker switch control on back. no AC adapter option) 5W max just under $200 See post below for a little overview/ review AOC E1649FWU - 15.6" 1366x768 14.8" x 9.3" x 1.4" 2.3lbs [no cover] 200nits on USB (no brightness control, and not actually as bright as the others? [?]) 8W max about $130 AOC E2251FWU - 22" 1920x1080 20.2" x 15.3" x7.6" [more like 2" thick at most parts] 5.8lbs [no cover] 150nits on USB [optional AC, required for full brightness ? ] 10W max about $160 Soon to be out: Mobile Monitor 'Field Monitor Pro' & 'Monitor 2GO' @15.6" and the 'Field Monitor Pro' @ 15.4" -these are supposed to be sorta like convertibles but with only the screen and no motherboard or anything like that (its only a screen), they do seem to have USB hubs on them and one version has a keypad while the other has a 'ipad dock port' All the rest: most are listed here DisplayLink Store :: Monitors Micro connection monitors - the only decent ones I've run across thus far are the GeChic 13.3" ones on newegg; but they don't seem that great being only 13.3" 1366 x 768 HDMi only, draws power from USB anyways, and not a quality product from a name-brand manufacturer. Oh, and if any of you have one of these devices or something similar please share anything from a short bullet points to a mini review of it here!