The wait (if indeed there was such a thing) is over! I have today uploaded version 0.002.00 of the controller code and supporting libraries to the Mk1 downloads page. There is other useful information on the other pages that should help you get the code running.
This source code is made available completely free of charge as a service to the amateur radio community and is released under the terms of the CC BY-NC-SA 3.0 license. https://creativecommons.org/licenses/by-nc-sa/3.0/.
Please note most carefully that this is an alpha trial version. There are almost certainly bugs yet to find and just because it works in my development/station environment doesn't mean it'll work for you. But as I think the likely audience will be computer literate Arduino fans who can do their own software development and maintenance, I am hoping this will not be a problem.
There are certain hardware and software dependencies that I have tried to document as I have gone along but I may have missed something along the way. What I hope for now is that you will be able, if you so choose, to compile the software and upload it to your Arduino Due. As you'll have quite a lot of hardware to build as well, that's probably about the best I can do for now.
My real hope is that this project and the release of all its code serves as a stimulus for others to take up the challenge and write more - and almost certainly better - code. I make no claims to being a C programmer, in fact I rather dislike the language, but it is the Arduino language of choice and needs must. I'm sure someone with better C credentials will be able to make something far better.
One final request:
Maintaining this Blog and writing the software in such a way that it can be let out on its own has been a considerable undertaking. I am happy to do this as a service to the amateur radio community.
If you do download the code and, in the fullness of time, start using it, please do let me know how you get on. Even if you don't plan to use the software but you find the Blog interesting and informative, please tell me. I always appreciate comments to my Blog posts, so please don't just take and give nothing back in return!