Christopher Franchi writes:

I'm here to confirm (without a photo) that there was indeed 
a Kook-Aid t-shirt.  I stumbled across it at a local Detroit 
area Korvettes department store (now defunked) when I was 
about 10ish (1976).  They had Blunder Bread and Wormy Packages 
too. I begged and pleaded my parents to buy it for me, but 
no dice.  As a last resort, I recall spending the entire 
rest of the shopping trip standing in front of that shirt, 
in hopes that my parents would see how badly I wanted it.  
It didn't work.