I've had an email from Cornell which says (extracting the relevant bits):
After I emailed them back they replied
So it sounds very promising
I think it's basically the closest they can say to "admitted" without breaking the agreement they have with the other ivies not to release decisions before the appointed date.
I had a 33 in my ACT split across 35 in math, 33 in reading and english and 31 in science (The ACTs curve for science marks is awful
) and in my SAT IIs I had 800 in Math II and 760 in Physics. According to the ACT's comparison, my ACT result is effectively equivalent to getting about 1460 in the SAT I.
My ACT wasn't super outstanding but I did it in one take along with all of my AS exams so I think they may have also taken that into account. I sat my SAT IIs twice however; but only because the first time I bubbled on the wrong page (Cue facepalm).
I would strongly aim for very good scores -- Especially for mathematical subjects you'll want 800 or as close to 800 in Math II and another relevant SAT II, since 800 is quite common for Math II.
In terms of SAT I / ACT, most colleges release their 25/75 percentiles for their enrolled student body. I would highly recommend trying to get at or above the 75 for any college you apply to -- That means you'd be one of the best quarter of students if you were admitted so you have a strong competitive edge there. That said, it's not necessary by any means. Plenty of people get admitted with lower! (Ergo up to 75% of them getting admitted with lower!)
I won't hear back with conclusive replies from any until the end of march though.