You're not alone, kingIZZZY! This is something I've been thinking about for months!
My project has similar requirements to yours: I don't care about size and weight, as long as it fits in a carryon (and it is going to be huge - I ordered a 24-inch LCD yesterday). It has to use standard desktop parts for replaceability and upgradability. I also want to reduce setup / takedown time as much as possible by leaving everything plugged in, using retractable cords, and space for all peripherals to dock into the main unit.
I'm curious, though, why you decided that the LCD has to be removed and put on its own stand. How about replacing the hinges with laptop-like hinges that hold their position (called friction hinges), and running the LCD in the lid of the open case? The drawbacks I can think of are 1) the monitor might not be at the correct eye level, and 2) having the computer on the table in front of you takes up a lot of desk space. However, I believe the ease of setup / takedown and the benefit of not having to carry around a separate monitor stand might be worth these drawbacks.
Second, if you absolutely don't want to put your computer in another case for travel, and it has to be waterproof, you might be interested in Ben Heck's Pelican Case Xbox 360 mod (http://benheck.com/12-24-2008/pelican-case-xbox-360
). You'll definitely need a bigger case for a desktop computer, but it should be informative to see how he overcame the challenge of not being able to cut any external openings into the case.
Third, do you have any tips or sources for retractable cord reels? I think I'll need 3: power (I plan to join the monitor and power supply cords), keyboard, and mouse. And before anyone mentions wireless peripherals, I'm a hardcore gamer and definitely notice the latencies. Plus, I don't want to deal with batteries.
Finally, would you mind elaborating on that bit about taking out the hardware components for security?? I fly with my current microATX box and they've never made me do that!