I like Glen a lot, and I definitely prefer this spelling. I think it will come back into style eventually, but it's too soon. The most common age of a man named Glen in the U.S. is 53, and the most common age of a man named Glenn in the U.S. is 48. [Data from Wolfram Alpha, for the year 2018.] So I'd give it 20 or 30 years before it is popular for babies again. And I can also imagine it going to the girls (unfortunately).
Glen Murakami is an American animator, animation director, and producer of Japanese descent. He is best known for his work on Batman Beyond, Teen Titans, Ben 10: Alien Force and Ben 10: Ultimate Alien.
I didn't like this name at first, but it's growing on me. I certainly like this more than the other spelling, which makes the "n" seem rather drawn out.