WebPass ( https://webpass.rkeene.org/ ) is similar -- its syncing is done by encrypting the list of sites (note that passwords are never stored or encrypted) and sending that from one client to another (no server ever stores the encrypteed list of sites).

It's also an iOS/Chrome webapp so it will act like a native app in some ways.

It's also a single JavaScript file which isn't too heavy. The sync'ing is done by a simple process that reads what another client writes implemented as a CGI talking over a FIFO.