Tux Jigsaw is "Linux from Scratch." It's not really a distro, but rather a guide that walks you through configuring an entire Linux distro from the ground up.
Gentoo is a distro focused on compiling pretty much everything from source locally.
Yeah, honestly you can replace Arch with Gentoo. Arch is for when you don't have a life for an afternoon or two while you're getting set up. After that it's smooth.