You could try reading this thread
for some inspiration. The Patch Commander thingy someone talks about at the end is located here
. I'm not sure how far you will get without an unpatched exe though. Apparently reverting is not easy if you don't have an old unpatched copy.
Not sure why you'd really want to go to 1.03 though - everyone runs around backwards trying to backstab people. Makes for lame fights.