Based on your question, I don't think you really understand what Armbian is. First off, armbian is the build framework used to build images for SBCs. Secondly Armbian maintains source code for kernels and uboots for various SBCs. An Armbian image is basically the output of the Armbian build framework that combines Armbian kernels and boot environments with essentially stock ubuntu or debian user environments. Armbian isn't really a separate linux
So in some ways what you are specifically asking for doesn't make sense. But I do understand what you are trying to accomplish. You essentially want the armbian build framework to combine your kernel/uboot with the ubuntu/debian userspace to create an image.