
There is an interesting discussion at the Star Trek fan message-board Trek BBS called "Is Shatner Really Bald?" Link here. On page 3 of the discussion, user "Adm Drake" claims that:
"Shatner went through various pieces over the years, waring [sic] a top piece in the first two Star Trek movies. He switched to a full piece by the time Star Trek III was filmed. By the time of Trek IV, he was wearing a weave which is simply a wig sewn into the existing hair to keep it more secure. Shatner ditched the wig in favor of a transplant done in 1999."
Another user "Therin of Andor" mentions that:
"Interviews from the 60s with makeup artist, Fred Phillips, mentioned that, to save the stupidity of Phillips having to apply a bald cap over a toupee for the final stage of Shatner's "The Deadly Years" makeup, Shatner simply whipped off the toupee."

If anyone out there has these, please let us know. Some other great finds would be a Joan Collins television interview in which she described Bill Shatner's baldness, and a radio interview done a few years before even Shatner stopped playing hardball about his toup wearing - in the interview, he was asked if he wore a toupee and became very agitated at the questioner. Are these things out there somewhere? Shatner toup fans, please help us if you can.