That was going to be the MD-12, I believe. But they did not have the resources to fully develop it. Following the short-lived early success of the DC-10, the only plane they managed to sell large numbers of was the MD-80, a segment where margins are not huge (it had to compete with the 737, Fokker, and later, the A320). Boeing basically made the money to buy MD because they had a couple of products with excellent margins - the 747, 767, and to a lesser extent, the 757.
Margins on aircraft more or less increase faster than the size of the plane. The small commuter plane business is a bloodbath with a lot of competition and not that much money to be made. 100-150 seaters are a little better, but the real money is made on the wide-body jets.
The only thing you should feel when shooting a terrorist: Recoil.