Is there a cloud storage solution with the following features:
partially copied locally. Not fully like dropbox so it can be larger than the local disk. Not fully in the cloud but just a local disk for recent data, i.e. its fast and works offline.
good client side encryption. No possibility or temptation for the host to decrypt my files.
can be shared by multiple machines
optionally some backup mechanism.
osx support, iOS optionally
I imagine a large client side encrypted virtual disk with partial local backup, i.e. encfs with an intelligent sync to cloud.