Well, it would turn out that there is and to find out we need to turn to our trusty friend, the transaction log.
As we know, the transaction log will squirrel away an entry each time that a row is modified. We can count up all the LOP_MODIFY_ROW, LOP_INSERT_ROW and LOP_DELETE_ROWS entries for our transaction and that will tell us just how many rows our transaction has altered so far.
Click through for a script, as well as an important disclaimer.