First... rematch? That means that she battles with the player? Wow! That means that she could have her own sprite too.
Also, even if Chieko leaves after certain events, then I'm sure that the data doesn't terminate itself. If we compressed such "patched" game into a ROM, we could be able to look through the data of those events (all dialogues, sprites etc.) or even access them in-game.
But I know Japanese people, they would never agree on this. The other option is BUYING that site owner's cartridge (if he/she still has it and it's still working) but I don't think that anyone would do that.
As for PokeSpe, yes, this is really disappointing. If Kusaka did it the right way, the world would never forget about Chieko...
Also, what do you think about the possible release of GB/GBC games as 3DSWare? What would they do with PCC and Mobile System if Crystal was release for 3DS's Virtual Console? Would it just leave it as-is and PCC will just stand there uselessly, or would they just delete the PCC (along with Game Corner)? Or maybe they'd use Wi-Fi to "emulate" the Mobile System (this way, we could use it in English version too)? This would be amazing, but it's probably not happening.