Probably your best bet for linux pre-installed on a laptop is to purchase one from Dell or HP. Tier one vendors began slowly introducing linux OS options over a year ago. HP and Dell both offer models with Ubuntu installed, which is debian based.
Another option is EmperorLinux
But I would consider that the larger proportion of laptop users that have linux installed - downloaded and installed the distro of their choice onto a laptop that originally had Windows installed. Installing Linux is usually much easier than installing Windows and takes much less time. An attractive option for new users is to dual-boot Windows/Linux and will give you a egress option for those times in case the frustration factor sets in...
One question, is there a reason why you would like debian installed?