There are no current plans to have the 'S' treatment for ZEN (which would be a little more complex than it sounds), so I might sooner suggest either upgrading to a ZENith or waiting for the successor range to follow the Mk3 which is likely to mostly, if not entirely, SSD-based.
I'd not recommend swapping a ZEN Mk3 to a ZENmini + LPSU as this would be a downgrade. More basic motherboard, a lesser PSU section, lesser chassis etc so not really worth it just for the SSD.
Was there a particular motivation for wanting the SSD specifically?