Well, if it's going to be a tail light like this, it's got to be LED. Not that I think it has to incorporate a new fangled component, but due to the shape. There's really no other choice for it to work correctly. So here's my initial layout. The solid red circles are the running lights, the red rings will be the actual brake light.
I also toyed with the idea of incorporating turn signals but, with keeping in mind that this is supposed to be a "home brew" project, that was definitely a no-go. I drew up several different ways but all required multi-layer PCBs.
This layout is going to be restricted to what I can do at home. Sure, I know lots of places where I can have a multi-layer board manufactured but, again, home brew.