my dept was forced to switch over to win 8 earlier last year as we were approaching a new school year, we had to be ready to deploy windows 8 to the campus.
since our school has a laptop program, we had to figure out how to customize the metro screen and implement it on 650 student laptops (gr.7-12) and about 100 faculty/admin staff laptops.
using a custom built appsFolder.itemdata-ms file, we have it linked to a batch file and ran that after the first time they logged in so that their screen looked like everyone else's. not the most elegant way of doing it, but it works for the most part