Opening typescript file in DOS mode?

[Roy Smith]

On unix, files normally have newlines as line terminators.  But, if you run 
the "script" command, you end up with CR-NL pairs, because it's grabbing 
the raw terminal output.

If I open the resulting typescript file in emacs, I see all the ^M's at the 
ends of lines (not fatal, but annoying).  Emacs will automatically open 
CR-NL files in DOS mode, but the first line ("Script started on Sun Mar 13 
08:59:06 2005") only has the raw newline, which seems to make emacs think 
it's a normal unix text file.

I can force emacs to open the file in DOS mode interactively (C-X RET c dos 
RET C-X C-F typescript RET), but that's a pain.  Is there any way to get 
emacs to read past the first line when deciding which mode to open the file 
with?