I finally have a fool proof way to run Windows XP xen guests and will be posting a HOWTO on it.
This work took weeks if not months of trial and error to come up with a solution that works without much effort.
I will provide a generic Windows XP image that you can buy from me that is 100% ready or you can make your own iso and do a install to the image file you will need to create.
The tentative price for the Windows XP xen image will be $500 and trust me it is well worth it.
Stay tuned to this thread for a update in the next few days about this !!