Actually, the nightmare I had modified originally dropped one of the Keystones that was originally going to be required to reach the End. There are three Keystones listed in NEI.
Now, I'm planning on the three Keystones coming from special withers. Each will be created in a different dimension, Deep Dark, Nether, and the Dream World.
0o0o0o00o, really cool idea. Those bosses sound like they have some very cool possibilities. I've always wanted to fight wither that weren't absolutely pathetic. Very, very excited to see how they turn out.
Any plans to add the HQM mod into the pack in the future(obviously not soon, quests are hardly a priority for this pack), sort of as a way to lower the steep learning curve of the pack? For instance a quest to make your first flint tool, boosting your pickaxe, etc. Pretty much as a tutorial, so that people can get frustrated due to mobs or hunger related deaths, rather than not knowing what to do next because they don't know that you need to use flint for your first tools, or you need to get steel from the nether, or you need to craft the end portal instead of finding it in the world, etc.