Not only technically very difficult, but requires the MS VC++ team to be complicit and silent. I'd put it pretty far down the list.

Not that hard to imagine anymore, with National Security Letters and whatnot.

Then compile it with gcc on cygwin and/or llvm and compare.

Then it won't match. Your only hope of getting exactly the same binary is to use the same compiler with all the same settings.

It can easily be reverse engineered.