Using a tile layer for a large sprite or two and traditional "tricks" for more than 2 layers of parallax isn't anything new and there isn't any other way to do these things with the Genesis hardware.
We already have a thread dedicated to games which do more parallax than can technically be achieved "natively".
I designed some parallax for Henshin Engine which simulates two overlapping tile layers with a layer of translucency/shadow in-between, which has multiple levels of translucency. This is ompossible to achieve on SNES natively. But I don't pretend that it's anything more than dynamic tiles or that it's been done several times in the past.

