For all-around customization, Zedge is the top choice. For creating your own sounds, Garage Ringtones and Custom Ringtone Maker are excellent, with high ratings and positive reviews for being truly free and functional.
Install → hide status bar → set dashboard wallpaper → add red widget clock.
For a more interactive "piece," you can install apps that mimic talking to KITT.
Do you prefer a or a dashboard packed with functional buttons ?
Use (free, no ads) to create a retro-futuristic icon pack with red/black/blue gradients.