system installation - Is there a simple way to create a custom Install Media that uses a customized Ubiquity installer?

I want to know how to create a Ubuntu based Install Media that has an customized Ubiquity installer that has custom branding and custom packages. I don't just want to create a ISO file of a system, I want an installer.

I also don't want to create my own mirror, just want to use the default Ubuntu mirrors.

(Pretty much I want to create a custom Ubuntu flavor for myself)

I can't find how to do this in a simple way anywhere. I AM READING the DebianCustomCD page on the Debian Wiki but it doesn't go over editing the Ubiquity Installer which is one of the main things I am trying to do.