creating Ubuntu VMs using packer

Has anyone here managed to use packer (See www.packer.io) to create Ubuntu Desktop VM packages,which can be used with virtualbox, amazon etc ?

I've managed to use packer with Cent OS and Ubuntu Server editions, but for some reason no matter what I do I simply cannot connot configure packer to automatically build me a vanilla Ubuntu Desktop VM, for me to use with vagrant to create a variety of custom Ubuntu Desktop VMs for various different purposes.