Delay live playback from video camera

Hello, I am a circus coach and I would like to set up a video system that I can have a video camera capture a particular trick such as a person flipping off a Russian Swing and then play it back to a tv with a preset delay such as 20 seconds.  I have successfully achieved this with an old tivo in the past but it is very difficult and needs to be setup each time it is used.  It is a great training tool but I have not been able to find an easy and affordable way to do it.

I would also like to be able to store video clips of past acts and acts from other shows that can be catergorized and viewed for inspiration by the performers.

Thank you for any help you can provide

None of the WDTV can record anything, they need for the media to be already sotred to be accessed.