Dear Warren,
I think that's a great idea! Although I can only imagine how conflicted you must be about designing, making, and marketing such girly things. Too bad that the interest in jewelry for men seems to be so low. But is it? Maybe for men in their 20s? I'm sure you'd know or have a much better feeling for this than I.
If you don't mind, I'd like to provide you with some wisdom on creativity. I've studied a lot about this and have a story to relate.
A pottery class was divided into two groups. The first group was assigned to make one pot for the semester. They were told to make their designs, consider it all very carefully, and then make it. At the end of the semester a committee would judge which one was best.
The other group was advised to make as many pots as they could, every day, every week. They would also choose their best at the end of the semester, to judge which was best.
Maybe it's obvious but the second group won by a landslide. Focusing on perfection doesn't work.
So make jewelry, lots of it. Like writing, don't worry too much about having a complete idea to get started. Just start. Anywhere. Some of it will suck. But maybe some will generate more ideas that you can riff on.
And do it for the fun of it, for the joy you'll be providing your customers. If you create that joy the money will follow.
Best of luck with this,
Emma