This is the men's bags section of ysl.com:
http://www.ysl.com/us/en/onlineBoutique/Men/Bags.aspx
This is the men's Muse briefcase:
http://www.ysl.com/us/en/onlineBoutique/Men/Bags/BusinessBags/P-Muse-Briefcase.aspx
Is this the same one?
http://www.ysl.com/us/en/onlineBoutique/Men/Bags/P-Muse-Overnight-Bag.aspx
I just bought one! LOVE IT!