I would be excited to attend, but with the size of this community, I don't think you'd have a conference; I think you'd have a dinner party.
1) U.S.
2) Why care about Arc (esp. relative to Clojure)?
Future direction(s)
Lessons learned, and the applicability of those lessons to other languages
Applications (e.g., Jarc on Google App Engine)
3) Maybe... But I'm really more of a dilettante than a hardcore hacker.
4) Spring is best, but it doesn't really matter