Mike, here is what I did for Ubuntu 14.04 and android-x86-4,4r1.
1. Installed android-x86 to the same partition as Ubuntu. No format, no grub and RW for system.
2. Changed two lines in /etc/default/grub as shown below:
#GRUB_HIDDEN_TIMEOUT=0
.
.
.
GRUB_TERMINAL=console
You need to comment out "GRUB_HIDDEN_TIMEOUT" in order to see the grub menu at boot.
"GRUB_TERMINAL" is optional.
3. Made the /etc/grub.d/40_custom file look like this:
#!/bin/sh
exec tail -n +3 $0
# This file provides an easy way to add custom menu entries. Simply type the
# menu entries you want to add after this comment. Be careful not to change
# the 'exec tail' line above.
#
menuentry "Android-x86-4.4.R1" {
set root='(hd0,1)'
linux /android-4.4-r1/kernel quiet root=/dev/ram0 SDCARD=/dev/sdf1 androidboot.hardware=android_x86 video=-16 SRC=/android-4.4-r1
initrd /android-4.4-r1/initrd.img}
4. Make sure that 40_custom is 755 and then run update-grub: