It shouldn't be too hard to find XP drivers for the new devices - I've successfully switched over a few Sony Vaio's from Vista to XP.
If you do get stuck, look on the website of the manufacturer of the device you need the driver for. 9 times out of 10 a search for "Vaio XP Drivers" will yield no results, but if you look for the specific device you usually get lucky.
Good hunting.
Also, try contacting the manufacturer directly - I even got Sony to send me a disc with the XP drivers.