This is how I make my mini arcades with off the shelf parts. It's made with Kindle Fire Arcadie's as the shell with plug and play video games for the internals. It also uses a 5" LCD for the display. See my Galaga video for the build howto.
Kindle Fire Arcadie (http://bit.ly/amznfirearcadie)
5" LCD (http://bit.ly/ebay5inlcd)
Plug & Play TV game (http://bit.ly/ebaypptvgames)
USB speaker (http://bit.ly/ebayhamburgerspeaker)
Mini Arcade Machine - Galaga (How to make it with an Arcadie)
Mini Arcade Machine - Bubble Bobble