Coming soon or you can submit one.
Originally created Elvm, the In-Game Account switcher allows you to switch between any valid Minecraft account without completely exiting the client. This way you can play, then go to the title screen and let your sister, brother, mom, dad, wife, husband, friend, neighbor, whoever happens to be there with a valid Minecraft account to play, all without having to exit completely out of the client.
This mod has a builtin update checker.
All Rights Reserved with one caveat; the author requires you to at least try to build a mod first, send him the link and he’ll authorize you.