Looks like you have some great suggestions. I would go with something r/t what he likes to do. *
I have some designs on my site that are great on a towel for males.
Hobbies, sports, etc. My brother loves the sea and anything nautical, and I once embroidered dark blue towels for him with yachts, ship's wheels, anchors, and so on. He was delighted with them. Embroidery Library have lots of designs for men.
look at these sites
1.it's henri's and many funny designs.(animal/movies/ tools) take a look.
2. for men
4 a little strange but certainly for a man.
look for hobbies as suggested by ansalu or a simple embossed letter.
Has he hobbies or did he like a special kind of music? Some animals, hunting, biking, motorbikes, trucks? Or loves he to travel? Maybe you find something for him :o)
Hobbies, oh my gosh! His is spending his waking hours at the gym or running marathons!Thank you for the ideas.