Sure, Android includes a non-GNU userland and does not include the GNU userland, but the GNU userland (including even regular old glibc) will still work if you put it on the phone yourself, even though your phone doesn't come with it. There are even Play Store apps that download and install an entire Debian/Ubuntu ARM distribution in chroot on Android. I wouldn't want static binaries for everything but a shell is critical enough that I'll make an exception.
Thanks for the mkshrc script. It works fine in adb shell from /system/etc/mkshrc but doesn't seem to work in apps like Terminal Emulator (?) or ConnectBot's local terminal.