Hey, if this topic is still running, then, I have a great idea.
There has been something like this on the internet for a LONG time.
The Pokemon fan base on deviant art has actually made something like this.
This is known as, Fakemon. A topic within deviant art were artist make there own Pokemon. I'm not part in this community so i can't give any suggestions. But i do know its there.
Also the Elite 4, Lets be honest, Its not gonna be the elite 4 Its gonna be the League? right? Well that's what i think it should. So ya. You don't have to go with this, but its a idea. I know that would be REALLY hard to program in to leafgreen, but, whatever.
1 last thing. Remember that amazing battle frontier? Remember the fight with red? Innovation: COMBINE THE 2!!! what i mean is you should make the boss of each battle frontier the hero from a different Pokemon game.
I do realize this would be almost impossible to make. But ya know, after hacking Mario world, i know, in the land of computers, ANYTHING, can be done, with a little old fashion programming team and sprite teams.
Good luck to you and your game. Have fun. \\('w') ~wave~ "Work man, when you have a idea, all you need is a engine."