Took another lap today. 
Based on where the tree-removal and dirt-moving is happening, it looks more and more like a S&S 4D Freespin. I checked the corresponding plot size with SFGAdv, and it's about the same. 
  
Looks to me like it will run parallel-ish to the train tracks there, perpendicular-ish to the Superman lift hill. 
  
I'm not convinced yet... just an idea based on what we know and see right now. 
  
The 200' height limit is really a bummer.  50th Anniversary should be the year for a big, BIG addition. FreeSpin is cool, and all, but ya know... 
  
Either way, though, the park is solid. Lot of different ride experiences, and the best year for employees in a LONG time, I can tell ya that. Been a good season so far. Attendance at both SFoG and SFWW have been solid. They gotta be makin a KILLIN in concessions and stuff.