This question extensions from one of the answers to my earlier question: how to save user registration in the exe... (C#).
The idea itself is still very new to me, b
Here is a link to a piece of code I've used to append data to an exe. This is specifically for appending data without breaking the signing of the exe, but the principle should hold for just appending to unsigned executables.
http://blog.barthe.ph/2009/02/22/change-signed-executable/