Modular Synth Panels

I'm new to this forum. My first post. I hope it's ok to but into this
topic. :)

This topic interests me because I have also built a Haible Tau Pipe,
and I have not designed a panel yet. 

I was hoping that someone would figure out and share how best to
implement a dual color LED--mostly just because dual color LEDs are
cool looking and more unusual. For this reason, among others, I've
held off on my panel design.

Here's my question though--even though a 2-lead dual LED won't work
apparently--why wouldn't a 3-lead Dual work (with one lead common to
both LED headers? Or is this not the way that 3-lead LEDs work?