I like your grub.cfg file. I suppose it's possible to just forgo the grub-mkconfig in those other distros and just edit it manually all the time. As long as you don't install any more distro kernel packages there shouldn't be anything that automatically runs grub-mkconfig anyway.
I have Grub 2 in Sabayon on my laptop, and once I built a kernel I just did manual edits since. (Sabayon, at least at the time of my install of the rolling release distro, has an absolutely retarded Grub autoconfig. It INSISTED on using that mount by UUID syntax, even for kernels without an initrd, not even using fstab for guidance. It also buries your custom kernel images in a separate "Advanced" menu. Therefore, I never want to run that again because it causes me to have to do serious editing each time, or the system won't even boot)
So yes, I suppose that I am directing my hate in the wrong place. It's how the distros are using the autoconfig scripting that gives me the pox.