Hap- there are other wires going into the body of the calculator where the chip is, but I just don't see it being anything cool enough for the money. I found an old article by Forrest Mims about using a calculator as a stopwatch or counter by tying into the keypad wires to simulate pressing the equals button, then manually typing 0+1. Each timer tick or counter event presses the equals button, incrementing the display. This might be something like that. Still, that's a hefty connector!
I'm out of pocket for the next few days, but Mattel Armor Battle, Big Trak, Talking Battleship, Head-to-Head Football and Baseball are on the way. And I've still got those Entex card games, Funtronics Jacks and Plus One to work on.