Does Word 2007's equation editor have any equivalent to the
\overset commands in LaTeX?
I'd like to be able to stack custom text on top of
= signs, etc.
You can use
A more or less complete description of the formula language in Word is given in Unicode Technical Note #28, although the final implementation differs somewhat in some areas. Unfortunately this is the only real documentation that's there (I asked the author of the math typesetting stuff at MS :-)).
See this article : Superimposing Characters.
The basic idea is to insert a field of type equation containing
EQ \o (x,y) where x and y are the characters you want to superimpose.