I've actually been thinking about doing something like that when it comes time start putting my C4+454 project car together. Though I really dont like that style. I was thinking about adapting a set I saw in Ecklers that are for C5's.
No way! The coolest thing I've ever seen is my brother turning on his lights in my rear view mirror. I love the C4 pop-ups. Also the lines of the car look way better with the pop-ups when the lights are off than with the clear glass.
I would rather cut out the front license plate area and install two big driving lights behind a clear cover. that would look like a race car. The fixed lights are ugly to me, but that's just my opinion.