I could be wrong, but I thought only Muriel, Pam and Bobby knew about Lucy's rape, pregnancy and abortion. Lucy told Muriel she had been raped at the end of season 5 (which, if I recall correctly, was Muriel's last scene), and then Pam at the beginning of season 6. Pam helped her through the abortion and there's a scene later in which Pam tells Bobby about it.
The idea of "Texas justice" is a good one and would be true to several of the characters. It would be particularly interesting if Miss Ellie initiated it. The writers seemed less interesting in developing this story and its aftermath and more focused on getting the battle for Ewing Oil going.