Ok, keeping the stock LCD is VERY POSSIBLE. I could easily do it if i wanted to, and might just to show you guys how easy it would be,
BUT, you would still need to keep your stock headunit hooked up. Right now I have mine hooked up and its stored in the glovebox. All you would need (in my case, headunit in glovebox) is cut the wires that leads to the LCD and lengthen them about 2 feet or so. Then take the LCD and use superglue or find another way to keep it held up on the dash strip.
Now in my case, this would be fairly simple since I already house the stock head unit in my glovebox. But really, I have no need for the stock LCD since I dont use CD's, the time is on my computer, I dont have Auto AC. But possible, sure.