You are right, I think there is no chance for E-L adapters! It was a bold move from Nikon to make the Z-mount the shortest and widest. So you can adapt nearly anything and you have a lot of options for design. The only drawback is for their APS-C cameras: Huge mount for small cameras…The flange distance of E mount is a little bit shorter than L mount and it's only a little bit tighter than L mount. I don't know if impossible, but it's much more difficult than E- to Z-mount, because Z is the shortest and widest of all mirrorless mounts.