Yes, you can set up Win XP Mode for all users on a Win 7 platform.
Create your image exactly how you want everyone to see it when they open. You can even join a domain and pull down any credentials you have.
The actual image file (.VHD) will be in the following directory:
C:\Users\USER_NAME\AppData\Local\Microsoft\Windows Virtual PC\Virtual Machines
Take that VHD (it should be quite large..several Gb) and COPY it to a local, public folder. The Public folder is found under C:\Users. I created a folder called VM Users. Default name of the file you're looking for is Windows XP Mode.vhd
Log out of the Win 7 machine and have another user log in...I'm still assuming this is an Enterprise environment so they will log into the Domain with their credentials.
Have them go to Start All Programs WIndows Virtual PC and launch Windows Virtual PC (NOT XM Mode!). Give the name whatever you wish and set the RAM to whatever you wish (as much as you can spare!) and on the next screen, select "Use an existing virtual hard disk" and browse to the folder and .VHD your copied (in my example, C:\Users\Public\VM Users\Windows XP Mode.vhd) - hit "Create".
Voila! You are logging in to the same VM that everyone else can log into. Copy this VHD to any machine you need users to have this exact image. I suggest you disjoin the Domain and give the machine name a generic name that will be changed once it's on the next machine. NOTE: Newest research shows that running Sysprep (or any other kind of SID removal tool) is really unnecessary. I got this information direct from Microsoft.
A couple of big advantages here (obvious to some, perhaps not to all readers) is you can have a copy of the vhd elsewhere as a master of the image (assuming you're an Administrator of the image) and it appears as though it is not platform specific. We've been able to copy this image file across a couple platforms we have here (in our case we have Lenovo desktops and Dell laptops...no problems making the virtual machine work perfectly).