About the icons:
How about a small analog clock with a green check mark over top for up to date blockchain and a red "x" over the clock for not up to date. And even an hour glass over top if it's downloading. I figured it better represents what's going on. Whether the history is up to date or not. When they have the whole block chain it shows a green check mark. We could even have and hour glass over the clock if it's downloading representing that it's downloading. Animated hourglass would be ideal! Just like the hour glass by many mouse pointers...