bald cap:       used to make someone with hair look like they're bald



http://www.tgtoday.com/makeupandfashion/therightwig.html
http://www.tgtoday.com/makeupandfashion/wigcare.html
http://www.aaawigbiz.com/index-faq.htm
http://www.aaawigbiz.com/about_wigs/caps.htm
        Different types of caps.  They suggest "full custom" for people with no hair.  (expensive!)
http://www.ehow.com/how_110001_buy-wig-hairpiece.html
        They suggest a head band if you don't have any hair.
http://www.ineed2know.org/wig.htm