The attached source code in a hex editor in C#.
Hex Editor
Execution-Time Code Generator for C#
Don't waste your time. I tried to load a 29MB file into it (I have 1.5GB of RAM), the process got up to 800MB before it errored out with an Out of Memory exception. The UI also didn't update during the loading process. It needs sane memory management code and multi-threading, or at least a few DoEvents calls thrown in. I never did get to the actual "editor", so I can't comment on that, but who cares at this point. Seriously, it's not worth the time.