Average Screen to a pixel

What solutions have you come up for this cause I know I'm not the first to ask:

Client wants a solid color backdrop using LED's that is an average of the content currently being played off of Catalyst using pixelmad.

Problems:
A) What is the best way to get an average color of an overall output of a screen?

B) What kind of delays can be put in because the response times of LED's are unforgiving?

My thoughts:

In my perfect world (hahaha.... here we go).
I would be able to on a layer select a SUBMIX for my content (like how you can select to use another layer) then apply an effect like gaussian blur and max it out. This gets me a general average for a color, but it does not help with the response time.... this is where I think I ask Richard for a new effect.

PIXEL AVERAGE & TIMING: This effect will automatically average the media content selected and the response time to changes
Pram 1- Average area size (starting from center to entire area)
Pram 2- Response Time to Change (0 to 5 seconds?)

What do you think? Does someone have a better way?