Need Portable Back Up Solution

I do a lot of re-installations of Windows for clients at their homes. I’m looking for the best way to fully back up ALL their disks and then recontructing their data on the new OSs.

Currently I use Norton Ghost & DVD/CD drives. I would prefer to use a utility that would run completely from a disk and back up the data to a fireWire HDD or something. The point being is that I like to have the full restorability of Ghost but without having to install Ghost on the target system. The old ImageDrive software used to do something like this. I’m thinking I might need a solution for PCs that do not have a fireWire connection too…

Thanks for any help in advance,
-q