Yes, and it works!
Never mind the fooling around with root=UUID and all that.
All you need to do is add GRUB_ENABLE_CRYPTODISK=y to /etc/default/grub
Run 'grub-mkconfig -o /boot/grub/grub.cfg' and 'grub-install /dev/sda' (or
whatever the drive is)
then comment out /boot in /etc/fstab and run # umount /boot
# mount /dev/sda1 /mnt
# cp -r /mnt/* /boot/.
# reboot
This assumes you have drive sda where you installed LUKS encryption with
unencrypted /boot/, where /boot/ is partition /dev/sda1.
It works great! What a great feature of GNU GRUB v2. This works for Debian
unstable so would probably work for Trisquel too.