Features:
FREE! Source code available on request; let me know if you find problems or want to make improvements
Fully playable mini-game built into the frontend; George and R9-A fight each other for control over the game selection
Supports any program that you can run from the command line; if you can run it from the command line, you can launch it from Big Blue
Easy and simple game list configuration that won't have to be changed continually with each new version of an emulator
Runs at any resolution or aspect ratio (320x240 all the way up to 3840x2160 have been tested)
4:3 letterboxing for widescreen monitors
Theme that changes depending on the time of day
Pixel shader effects
Full sound and music
Built-in screensaver with a configurable timer
Ability to shutdown or restart computer when exiting the frontend
Configurable frontend controls
Left and right rotation for vertically-oriented monitors
What's unique about this frontend is that the frontend itself is a video game. Player 1 and 2 can fight each other to determine who gets to select the game.
I've also added a pixel shader so that the background scenery changes depending on the time of day.
Here's a video showing it running with letterboxing enabled and a 2 player game:
320x240:
640x480:
2560x1600:
Running at sunset with image scaling disabled at 2560x1600:
Running at night with image scaling disabled at 2560x1600:
You can download it here:
https://sites.google.com/site/bigbluefrontend/