Whooo, take a look at this nice portable from Acer: The Ferrari 3200
It actually has a 64-bit AMD processor onboard but it can run 32-bit code. So you can load up your Windows XP Pro 32 bit edition, and in the near future you will also be able to put the Windows XP Pro 64 bit edition on it. Here in Redmond, they are already running this and, its the ultimate developer portable machine. With Visual Studio 2005 and the .NET Framework 2.0 with 64 bit support, this is really the thing to have.