I want to do something similiar with mine but instead of the plain black floor i have now i want a reflective mirrored one or chrome so i can see the fan side of my GPU.
No idea whether to vinyl wrap it though or to buy a mirror sheet and cut it.
sound coo, especially with a water cooled GFX card with plexi top so you can see the liquid moving through it on the reflection... I worry about how obvious dust and fingerprints will be though