Intros have been integrated as of 7.8. You can download THIS intro under downloads then "Launchbox/Bigbox Official Media " and "Exploding Comet Intro"
To get this working. Simply download the intro, rename it to startup.mp4 the drop it into your ...\Launchbox\Videos\ folder.
Open BigBox/Options/general and set a startup delay/turn off bigbox logo on start.