I think dropbear is what sits under earlyssh. I'll look into dropbear-initramfs, if it's easier to work with than earlyssh that is a big plus in my book.
edit: early-ssh is hosted at https://github.com/gheja/early-ssh . Not to knock early-ssh by saying it's difficult to work with too - it's a great piece of software which has made my life a lot easier.
If you like early-ssh, I would like to suggest checking out better-initramfs. No dependency on systemd, easy to modify and build. I think it can do everything early-ssh can do. I use it to boot a variety of LUKS encrypted btrfs machines.
edit: early-ssh is hosted at https://github.com/gheja/early-ssh . Not to knock early-ssh by saying it's difficult to work with too - it's a great piece of software which has made my life a lot easier.