Craig:
I just returned from 2 weeks in Luxembourg doing genealogy research. Faber is a very common name there, as is Guillaume-maybe not as common as Smith is here but there are lots of them. I am sure you know Guillaume is French for William. It's possible our families could be related since given names tend to repeat in families. However, I doubt that parents would name 2 sons William unless they had middle names as well. To date I have not found a middle name for my Great Grandfather. My research turned up lots of Fabers but not my Great Grandfather nor his parents. Hours of reading microfilms for 7 consecutive days and I didn't find him! There are many microfilms that I didn't get to but can order from LDS for a rental fee.
There are a number of people who are taking pictures of the films in Lux. These will show up on Rootsweb or similar websites eventually. Keep searching for new Lux. websites and eventually you will find what you are looking for.
Nancy