Where can i buy a leather laptop bag for my 17 inch computer?

Here are some nice stylish bags for your computer!
David King: Compartment Dimensions:     17.5" x 11.51" x 2.5" 

Size:     12" x 18" x 7"
Weight:    5 lbs
Material:     Full grain vacquetta cowhide
Warranty:    One year against manufacturer defects

I like the Royce with all the extra pockets for items! ; )

Perfect for the new 17" laptops. This Genuine Leather briefcase is loaded with features and styling. Two front pockets, one for papers and incidentals, the second has 3 pen loops, a cell phone pocket and business card pockets. The large center compartment is padded to protect the laptop and has a Velcro strap to hold the computer secure. A large file pocket with a ID window and multiple card pockets complete this section. The entire case is lined with theexclusive striped moiré' lining.

Size:     18" x 15" x 4"

Or if you need something that can work on your lap!
Briggs & Riley's @Work Big Screen computer brief has a u-shaped opening, allowing you to work on your 17" laptop while it is still in the brief. Briefcases built for a lifetime, this piece features Briggs & Riley's lifetime warranty.

Laptop Compartment Dimensions:     17.25" x 13.25" x 2"