Get your band together and jump to a new alliance, make a new one for yourselves if you want. Decide first who will b leader and what the name will be. We did this before and lost someone in the jump but somehow found them again and we are still together as a band! Tell players to return to the old alliance if they lose you and send someone back to check nobody got stuck. You can leave messages in the old alliance chat. Make sure you appoint co-leaders so it doesnt happen again. Good luck!
I recommend having your group register here on the forums or get each other's contact info before you migrate. On the forums here, you can private message each other and keep in touch. You don't need to put too much personal info. Check with your group on the level of personal info sharing they are comfortable with. Good luck!
We've actually moved along with most of our members from one alliance we were in to another (but for a different reason, not because the leader was inactive). I started the new alliance and as a result became the leader and most from the old alliance followed and joined me at Global Realm. I suggest you do that since it worked out well for me.
Thanks for all the helpful advice. Many of us have left that alliance and have moved on; 11 of us have reunited as a new alliance. The old alliance leader has been MIA for 48 days. The others remain in an alliance without promotion or war. Thanks again