Anniev,
My spouse recently visited India after graduation on an OPT and had no problems on the way back (this was two weeks ago and the visit was certainly not under unavoidable circumstances!). The immigration officer at the port of entry looks for:
1) Valid I-20
2) Valid F-1 visa
3) Valid EAD Card
4) Job offer letter
5) Student ID -- not mandatory, but keep it at hand if you still have one (if your school asks you to surrender it, you can just tell the officer that)
In fact, in our case, the job offer letter was not even asked for (surprisingly!)...but you should certainly have a signed offer letter at hand. I know of other people who have successfully entered the country after graduation provided they have the above 4 documents.
I agree that there is a theoretical possibility that an officer can reject your visa at re-entry, but from talking to my lawyers, the International Student office as well as several other students who have had the same the experience, in reality they don't reject it if these docs are at hand.
Good luck,
Ascii
P.S. : Remember, I am not a lawyer, just sharing my experience and $0.02!