You're in the same boat as me. I cut the connectors and ran power/signal through one cable which allows me to plug it in/out quickly. Takes me 7s to remove the screen. (timed it ) Obviously not as nice a slide in/out design, but... it saved me a lot of time, maybe later.
VIA Epia II
256MB 266DDR Ram
90GB Wester Digital
Lilliput 7" Touchscreen
Mazda 6 Carputter > Click Me!
I am just going to have a sweater or some other article of clothing and I will just throw that on top of the screen when I leave the car. As far as the mounting screw goes, it isn't that bad to remove. Just keep it tight enough so your screen doesn't bounce around but loose enough so that one quick turn will release the screen completely.
AMD XP 2600+/512MB RAM/120GB hard drive
Opus 150W/DVD/GPS/7" Lilliput TS/802.11g/Bluetooth
I currently have a Pioneer WD6010 which is designed to be detachable. Unfortunately it is only a TV screen not VGA, therefore I have now got a Lilliput and am working on putting it in the dash. Considered having it on top and removing each time, but decided it would be far to awkward. The Pioneer I can do effortless and seemlessly and people who get in the car with don't even notice me doing it.