I really like option 3.

Have two sister sites with essentially identical setups and styles, one for speedruns and one for highscores. Have a link between the two at the top of every page, possibly even keep it consistent from game to game (so switching to highscore.com from src while viewing a specific game keeps you on that game)

I'm pretty sure there would be a lot of people willing to donate to the attempted purchase of highscore.com, I certainly would be.