Making a masculine card by hand is difficult. I have had a seriously difficult time with it. Here is a fathers day card that I think has some potential. It is a handmade and sewn greeting card that looks like a pair of jeans. Genius! I made this last fathers day. The card is full of custom stitching and I even created the graphic for the tag.
The pocket was fun and I even thought of making it an open pocket and sticking a $20 in there. It would be a fantastic card for holding gift cards.
Hopefully this gives you some inspiration for some masculine cards.