If your kids are into graphic novels, check out Classical Comics. Not only are they real, unabridged classics in graphic novel format, but they also come in original text (for example, Shakespearean English), plain text (modern English) and quick text (~elementary reading level modern English) so differentiation is a breeze.
I think the graphic novel format is perfect for Shakespeare's plays, which are much more understandable when performed than when read. The teacher's guides are designed for British schools Key Stages 2 and 3, which correspond roughly with late elementary and middle school in the states. They include activities, quizzes, and tests with copyable black line masters and answer keys.
We're using Henry V right now--original text for my reader and plain text for my non-reader, although I have to say the plain text is helpful even for advanced readers. I never really understood what the Archibishop's arguments in favor of war with France were until I read the plain text version, and I've read the play at least twice and seen the movie a half dozen times. The plain text also preserves Shakespeare's language where possible, so I don't think using that exclusively would ruin the educational experience.