Mine

#!/usr/bin/python

import os, re
arch = os.uname()[4]
if re.search('64', arch):
        arch_libdir = 'lib64'
else:
        arch_libdir = 'lib'

name = "XXX"
uuid = "XXX"

vcpus = 1
memory = 1024
shadow_memory = 16

builder = "hvm"
kernel = "/usr/lib/xen/boot/hvmloader"
device_model = '/usr/' + arch_libdir + '/xen/bin/qemu-dm'

boot = "dc"

pae = 0
acpi = 1
apic = 1
localtime = 0

on_poweroff = "destroy"
on_reboot = "restart"
on_crash = "restart"

sdl = 0
vnc = 1
vncunused = 0
vncconsole = 1
vncdisplay = 26
keymap = "de"
usbdevice = "tablet"
serial = "pty"

#       'tap:aio:/var/lib/xen/images/XXX/driveC.img,xvda,w',
#       'tap:aio:/var/lib/xen/images/XXX/driveD.img,xvdb,w',
disk = [
        'file:/var/lib/xen/images/XXX/driveC.img,hda,w',
        'file:/var/lib/xen/images/XXX/driveD.img,hdb,w',
]
vif = [ "mac=00:16:3e:12:0f:78,bridge=xenbr0,script=vif-bridge" ]