Where can I find a good, intensive hand-to-hand combat camp (for a
civilian) during the summer that runs for at least a week and is
preferably (though not necessarily) in California?

Hi! Thanks for the question.

I've found two summer camps from California which specifically state
that they offer hand-to-hand combat classes.

Shotokan Karate Institute
http://www.shotokan.com/bio.html 

Hwa Rang Do
http://www.hwarangdo.net/Contact.php (Contact info)
http://www.hwarangdo.net/art/ (profile)

Other "hand-to-hand" camps I've found are listed below.

TKA
http://www.tkasudo.com/history/HistoryFrame-3.htm

Team Delta Military Experiences
http://www.teamdelta.net/teen_boo.htm 

Intense Self Defense
http://www.intenseselfdefense.com.futuresite.register.com/

Professional Karate Academy of New Jersey
http://www.professionalkarate.com/classes-combat.shtml

Search terms used:  
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this answer, please ask for a clarification if you have a question or
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Regards,  
Easterangel-ga  
Google Answers Researcher