Yes the TRX680 has a bank angle sensor because of the EFI ..
I've heard stories of guys that do wheelies for several telephone poles ,that's a long way especially if the bike has an oil bath crank type .. I don't know how far a TRX650 Rincon would be safe to wheelie ..But I'm sure that when it's in a wheelie that most of the 2.9L of oil is inside the sub-transmission case ..