"Engineers" are one of the most respected professionals in our society. So i think, it is worth designing a shirt for them. Below are some of the t-shirt design for engineers that i have collected from various sites.
Engineers: courtesy of cafepress.ca
Get in Gear: courtesy of mechanicalengineeringblog.com
Trust me I'm an Engineer: courtesy of jumperlumps.com
Engineer:courtesy of spreadshirt
Engineers make difference: courtesy of engineeringedu.com
Reverse Engineer : courtesy s-cred.com
That's how i roll : courtesy of bwcnews blog
Electrical engineering: courtesy of cafepress.com