I don't think Zeiss is shrinking anything to make these. I'm pretty sure they're just rehousing key lenses from their ZM line. They might need a new optical design for the 85mm because the ZM is an f4 which is probably why they put out the 21mm first. They never usually release lenses this way, usually they cover the long end and work backwards.
Get an iPod Touch and a usb battery brick. Shoot all day.