I need to design a cost effective, but yet very functionally effective sideline review system for my highschool coaches to share with players to in order to make adjustments during the game. Instant Replay/ Play review is allowed in highschool sports and there are some companies charges outrageous fees for "reveiw systems". They are ipad based with wirless standard def cameras. Pretty slick but pricey. Here are some on the market.
http://www.echo1612.com/
http://www.replaylocker.com/
http://sidelinepower.com/sideline-replay/

I am hoping some of you guys will throw out how you would design it if you were given the same task.

We are already using a PC for streaming with vMix. I can not use this same PC as that will just not work. This PC has 2 BM Decklink Quad cards in it so I can pass the incoming cameras back out to the coaches for camera feed. My idea is this,

Take the camera feeds we have now and run them into a 4 Channel DVR (typically used for security). I have ordered this one http://amzn.com/B00VAYZO4C . There would be one person who would be saving each play and "coding" or titleing the play (ie Offense 3-1031) that could be Offensive play, 3rd qtr 10:31 is the timeclock time at snap of play or conclusion of play. I already have a Paralinx Triton HDMI Wireless Transmitter. So I can use that transmitter to send the video feed down from the press box to the sideline. The players would either use wirless headsets or walkies to communicate with the coach up on top of the pressbox where we are.

To make it really slick, I would take the video output of the DVR, run it into my vMix laptop so that they can run the telestrator. The video output would go from the DVR > Laptop via Magewell Dongle, and then out from laptop to sideline via the Paralinx.

I don't have the DVR in yet so I can't test anything until that comes in. I welcome all feedback and suggestions. Would you do it completely different? If so how?
If you would consider the method I outlined, but with changes what would they be?

Thanks!!
Tim

Thanks for the feedback. I started looking for software solutions after reading your post. I found this one http://longomatch.org/ price is good. But may have a little bit of a learning curve. I also see that only one live camera input can be used.

Do you have any other suggestions. I still think that using a DVR and run the playback thru vmix for telestrating might be a simple option but I may find out that is not the case after I begin real world testing it. Too bad we can't take the instant replay module and adapt it somehow to this need. I will keep thinking on it.