Just a thought...
I started working at a Running Room and had to get a lot of the specialized clothing to take out our clinic groups in the cold...but wearing so much athletic gear made me realise how hot I get wearing 'regular' clothes paintballing (I wore my Stock Class T-shirt all year for games).
Cotton just soaks up sweat and makes you so hot
. ... I would be interested if you ended up doing a run of moisture wicking shirts with these sorts of designs.