Hi Chris, sorry for the confusion about the Bricktronics Shield, wayne was confusing himself and edited his response to remove the confusion.
We have never tried the Video Game Shield with the Leonardo. I understand that the TVout library only recently added support for the Leonardo, so I will give it a try this weekend to see how it goes. The shield will definitely need a small modification to re-route the video signal source to the correct pin on the Leonardo.
I just tried to compile the TVout NTSC example for Leonardo, and it ran into the expected errors about missing definitions:
/home/matthew/Arduino/libraries/TVout/video_gen.cpp: In function 'void render_setup(uint8_t, uint8_t, uint8_t, uint8_t*)':
/home/matthew/Arduino/libraries/TVout/video_gen.cpp:89:2: error: 'DDR_VID' was not declared in this scope
DDR_VID |= _BV(VID_PIN);
If you are seeing errors about missing TVout.h or i2cmaster.h files, that indicates that the libraries are not installed in the right place. It's a little confusing, but the Video Game Shield ZIP archive and GitHub repository contain multiple libraries (like TVout, TVoutfonts, Nunchuck, etc). These folders all need to be inside your Arduino sketchbook's "libraries" directory, and can't be inside a Video-Game-Shield directory. Hopefully that makes sense, let us know if you have questions.
To conclude, it's not expected that the VGS kit will work with the Leonardo, but I'll take a look at it this weekend to see if I can get it working.