I just completed an interview with Sega Mega Drive/Genesis Collected Works author Darren Wall and Console Wars author Blake J. Harris, and Blake revealed details on a cancelled Sonic the Hedgehog movie that was to debut in 1995.
All the details will be in a piece he is writing for IGN, but you can hear some teases of the two treatments in the interview I am uploading now. I'll embed the video here soon, but for now here are some tidbits:
One treatment was a young real world boy turning into Sonic, another was a Roger Rabbit scenario of the real world and the video game world meeting - which is sort of like Wreck-It Ralph
I recall some magazines back in 1995 hinted at a movie being in the works, with the Archie comics confirming it and joking that Michael J. Fox was to play Sonic (not really).