You're generalizing. Some Dells do not use the same panels as Apple, but some do. I own a Dell 2007wfp with an S-IPS panel built by LG, which is identical to the LG S-IPS panel in my 20" ACD. They are most definitely the same, they look the same, the panels have the same serial number, and so no there is no reason why the Apple costs more in that case other than the logo on the front. Get your facts straight.
A monitor is more than just the LCD panel, there are other components to consider. As someone who works professionally within the digital imaging industry I'm pretty certain I have my facts straight. Your post is misleading at best and improperly informed.