However, I'd still like to get a grip on exactly how double-quotes are parsed by CMD.EXE.

Well, I'm mostly talking about how " are dealt with by the C RTL, for which it isn't that hard to obtain the source code, so just go read the code. How CMD.EXE deals with them isn't as important. It affects whether special characters cause you problems, but it has no impact on how arguments are split up, etc. (Unix defines the interface to programs to be a list of argument strings while Win32 defines the interface as a single command-line string.)