Thats such a good idea to take out the original carpet. I'm about to build a set of similar drawers and I'm going to possibly steal your idea. What are you using as handles? It looks pretty flush. Also the silver shiny stuff you're using on the floor, is that sound deadening?
Very well done...thank you for posting...this one's on my list. Mind sharing where you got your drawer slides from? 500# is stout!