Here's an online Vegas shopping link, it looks like as good a place as any to start. Also, if you can find or order a Las Vegas 'City Guide' they will often have shopping listings. That also makes me wonder if their are shoppers guides for European cities that might help out. Over here, I'd look on Amazon.com or Barnesandnoble.com for that type of tourist information.
Guide to Vegas: The Shopaholic
Amazon.com: Sinning in the City: A Girls Guide to Las Vegas: Kris Gundersen, Melissa Martin, Ginger Mikkelson, Tiffannie Bond: Books
Amazon.com: Las Vegas Shop!: Great Shopping Wherever You Are (Where to Shop Guides): Amanda Knoles, Joe Viesti: Books