Dell Business has the Kensington K64670US Portable Combination Laptop Lock for $22 - $5 off with coupon code D6WN9C7CCK?4C5 [Exp 10/15 at 5AM PT, 60 uses] = $17 with free shipping. About $20 elsewhere. While not exactly impervious, still a deterrent.
15% off Select Desktop & Laptop Accessories w/ code F6NH47Q05MZ11B [Exp 10/15 at 5AM PT, 3000 uses]
Deal has expired