I think I might have found the solution to help with getting an executable on the box using Teensy and nothing but the HID drivers of the OS. When I was researching around I found a VBScript for server side conversion of a file to base64. I then changed it around a bit and have adapted it to my Teensy. Right now, I have posed a tutorial on how to convert any file to ASCII Base64 encoded text then decode it using nothing but VBScripts. I am currently in the process of writing the tutorial on adapting this logic to the Teensy.
But to get you started, here is the tutorial on how to convert any file to ASCII base64 encoding: http://dabermania.blogspot.com/2011/03/converting-any-file-to-ascii-for.html