Pokémon Adamant is my first attempt at creating a Pokémon hack. I did have some ideas for it, though nothing was ever finalized nor decided (exluding a list of Gym Leaders I have in my Dropbox). Some of the ideas for it I'm actually reworking for the planned sequel of Pokémon ObsidianBlack & PewterWhite.
Really, this hack, if you can even call it that, was what got me into hacking Pokémon, so it was mostly created for me to get the hang of the tools that are used. It's practically certain it'll never be released.
As for changes, the Pikachu line was made legendary and a cave was even made where you can catch Pikachu. Some of the other existing towns, as well as that cave can be seen in the video that was once uploaded.
These are some screenshots from Pokémon Adamant.
This playlist contains more videos about Pokémon Adamant.