If you have the money gun then the Sony A7c claims to be the smallest and lightest full frame with interchangable lenses. The kit lens looks impressive, 28-60mm so not proper wide or zoom but it's tiny.
If you want full frame aren't your only real options Leica, Sony and Zeiss? I'd take the Sony. But personally I'd buy the latest x100 offering and go down to APS-C. In my humble opinion they're really very good, and very fun to use. Not super compact though.
If you have the money gun then the Sony A7c claims to be the smallest and lightest full frame with interchangable lenses. The kit lens looks impressive, 28-60mm so not proper wide or zoom but it's tiny.