Look at the Perfection Learning series; they are thematic. I have bought the whole series and pulled from each of the texts. There are various reading/interest levels to consider. From experience,it is hard to find all the short stories in one text.
or...
You could also differentiate/ jigsaw the unit and have the students choose an author and share the writings of that author. Have them read 5 short stories of choice and do a Publisher piece on the author. Annotate the short stories and do a PP with summaries or reflections to share with the class.This is much more meaningful and interesting than all of them reading the same short stories. Ryan has a useful LEO to have all the kids involved when the kids present, so all are active. It would be a 2 week project... minimum. You can make a list of ss writers to choose from(if you have to cover certain authors) or they could choose themselves.
1. BEst story I have ever read...most beautifully written and wrenching...for seniors THE SHAWL, by cynthia O...(??)
2. Am I Blue (it is a collection..but this one in particular is hilarious and makes an important point about homosexuality and homophobia etc...) 9, 10, 11 or 12th
3. More classic..(' THe Lottery", by Shirley Jackson "The Black Cat",by Poe, The Girl and the apple (not well written but touching though far fetched...went around on the internet)