Two ideas.
1) A hack of Phantasy Star II to re-create the text adventures into little episodic RPGs. I enjoyed the text adventures, but I would totally play them again in this form.
2) This one involves spoilers for Secret of Evermore, so don't read this one if that worries you, I Guess. There is a gigantic thread on the somethingawful forums about videogame myths, and one of the long-discussed ones was a hoax about Secret of Evermore having a late-cycle narrative shift from some kind of heavy dark psychological thing into something more goofy and kid friendly. Primarily that the people running their little failed utopian domains that end up being revealed to be evil robot clones were actually the real people, so like the Queen robot that falls to its death would actually be the real Queen killing herself, etc. This page is the source of it:
http://rainwoodworks.blogspot.com/2010/09/secret-of-evermore-was-one-of-my.html (and this one talks about actual pre-release changes:
http://www.unseen64.net/2008/05/14/secret-of-evermore-beta/ ). The main evidence talked about was the fact that the robot stuff could have been pretty easily shoehorned in, and that the earlier bosses in the game are mostly huge, screen-spanning monsters and the later ones are smaller, spritebased robot things. Also the general bugginess of the final area. They also discussed the game's commercial, which is pretty hardcore (
http://www.youtube.com/watch?v=dEu8wDAQuDk ) but dismissed that mostly as the type of aggressive/gross game marketing being used at the time.
That took a lot longer to explain than I intended, but anyway the hack idea here is to actually edit Evermore to match the myth. Get rid of the robot clones, tone down the goofier dialog, and hey why not just rename the game "Evermore" as it was originally intended while you're at it too? I think it could be neat, anyway, and if nothing else the hoax is fun to read about. I'd certainly play a hack based on it.