Just confirming that you can't use an ASIC for the SHA-256 part and a GPU for the Scrypt part. As currently implemented it's ASIC or GPU for SHA-256 and CPU for Scrypt, yes?

Or in other words, if I have a LTC mining rig with a high end graphics card, I could add some old ASICs and mine MED without either interfering with the LTC mining or short-changing myself on the MED mining?

Interesting idea.