This looks like ultra portable (i think there is 17" version also) http://www.amazon.com/ASUS-MS202N-Wide-Monitors-Black/dp/B002ZFCFP6
RE: ASUS MS202N - 20" Wide LCD Monitors I took a look at the specs... 20" wide, resolution only 1600 x 900, weight 10.7 pounds, $150 I passed. No need to go further. These days anything less than 1920x1080 would not be satisfactory. Be it less attractive being heavier and more expensive.
I am looking for the same set up and this is the only set up that make sense, two laptops I haven't tried it out yet. http://www.maxivista.com/ MaxiVista allows you to use a Laptop as a second monitor for your primary computer. No extra multi monitor hardware is required. Simply extend program windows across multiple screens as if it were one big monitor. Increase your productivity by using a multiple monitor software.
Part number: 1452DS6 ThinkVision LT1421 gives mobile professionals a second screen for on-the-go use in displaying spreadsheets and making presentations. At under two poun...
RE: MaxiVista allows you to use a Laptop as a second monitor for your primary computer. I have used MaxiVista before. It has issues of its own when you use it for traveling. It relies on a network connection between the two computers. #1) From what I have experienced, the throughput of these network connections at the hotel (mostly wifi now instead of a landline cable) is usually just marginal. It's not even adequate for running the trading app, let alone having it to move display data. #2) They typically have some kind of security measures on these hotel-provided networks. With it they may block the traffic from one laptop to another.
What about a rel dual screen laptop, which seems to be what the poster had in mind? http://www.gscreenlaptop.com/ 2x 17 inch IN the laptop.
If internet is wireless - link both laptops with ethernet patch cord and assign static IP to each Local Area Connection ( your wired interface ). If internet is wired - use a hub or a small router/firewall in front of the connection
Take a look at Toshiba 14-inch USB Ultra-portable Mobile LCD Monitor. Only one cable for power and video ..hassle free and portable http://www.amazon.com/Toshiba-14-inch-Ultra-portable-Mobile-Monitor/dp/B005F0IKHA/ref=pd_cp_e_1 check out the amazon video