That's exactly what I do. I have a new machine at home and an old at work. I use an 8gb USB stick to keep my profile on, and I move any savegames/dlc/arcade titles I want to play in the office onto it. It also means that I can download arcade titles in the office as they release, and then transfer them to my 250gb HDD when I get home.
The profile signs in where ever I plug it in, and then it's all active.
That's excellent to know, thanks Derblington.
Should i ever opt to buy a new slim version, well cave in actually as i'd really rather like one,and end up having two 360's in different rooms of the house this is how i planned to get round any drm/save issues. Nice to know it'll actually work like i hoped it would!