Here are the final results of the two surveys:
Open Public Survey
23 of 65 have been to a Xen Summit in the past
NA Xen Summit -> 15 YES / 16 MAYBE / 34 NO
EMEA Xen Summit -> 38 YES / 15 MAYBE / 12 NO
Xen Summit Attendees from XS AMD 2010
25 of 25 have attended Xen Summit
NA Xen Summit -> 18 YES/ 7 MAYBE
EMEA Xen Summit -> 4 YES / 11 MAYBE / 10 NO
As you can see, there is support to host the event in Europe as well as North America. I will be talking with more people in the community about this as I work toward a final decision. Thanks for your help in participating in the survey.