Yes, this interface. This is what I've been waiting for, since I saw Yves Baclan do it. Although I think he uses the concept a bit more artfully -- creating movement or adding information by playing with the layers on the original frame -- I think your execution is the dead-simple version that can be most easily utilized by the majority of web comic creators. Expect a phone call this weekend.
This links to the thing I mentioned on Twitter about e-print formats. But basically -- look, Flash. It works everywhere. It's already here. Stop trying to re-invent the wheel, Longbox.