A "middle name" for William?

I love, love, LOVE Thaddeus. It's been on my list ever since I had a client by the name of Thaddeus. It's such a strong, masculine name, it's not a very common name, and I can tell you from my personal experience that it transfers well into real life (the Thaddeus I met carried the name well). I really like Thad as a nickname, but I like the name itself so much I don't think I'd use a nickname too often. I think William Thaddeus goes well together. Wonderful name!