We were so close before, all we needed to install was the proper kernel.  Confirmed working on TKL Core 10.04 LTS (32-bit) appliance.  Thanks JedMeister!

Ubuntu Guest Console (Configure Guest):

1. apt-get update && apt-get install linux-image-generic-pae
2. cp /etc/init/tty1.conf /etc/init/hvc0.conf
3. nano -w /etc/init/hvc0.conf (replace all tty1 with hvc0)
4. shutdown -P now

Citrix XenServer Console (Configure XenServer):

1. xe vm-list power-state=halted (write down UUID for TKL VM)
2. xe vm-param-set uuid=<UUID> HVM-boot-policy=
3. xe vm-param-set uuid=<UUID> PV-bootloader=pygrub
4. xe vm-disk-list uuid=<UUID> (find VB disk UUID)
5. xe vbd-param-set uuid=<VBD UUID> bootable=true
6. Start appliance and restart XenCenter Manager

Ubuntu Guest Console (Install XenTools)

1. mount /dev/xvdd /cdrom
2. dpkg -i /mnt/Linux/xe-guest-utilities*i386.deb (OR dpkg -i /mnt/Linux/xe-guest-utilities*amd64.deb for 64-bit appliances)
3. umount /mnt
4. sudo reboot