I was looking for an easy way to clone a VM without VirtualCenter and came across this, which worked like a charm, bits of which I had done before for other purposes...

http://hsukumar.wordpress.com/2008/05/14/esx-clone-without-virtual-center

So I came up with a little automation, good for when you have to "create a few"... Change according to your datastore!

Script: clone-system name-of-source-vm name-of-target-vm

SOURCEVM=$1
TARGETVM=$2
DATASTORE=/vmfs/volumes/MY-VM-STORE

mkdir $DATASTORE/"$2"

vmkfstools -i $DATASTORE/"$1"/"$1".vmdk $DATASTORE/"$2"/"$2".vmdk

And I then enhanced it a bit more, to also check for a second drive, and allow for multiple datastores

SOURCEVM=$1
TARGETVM=$2
DATASTORE=/vmfs/volumes/$3
DATASTORE2=/vmfs/volumes/$4

mkdir $DATASTORE2/"$2"

vmkfstools -i $DATASTORE/"$1"/"$1".vmdk $DATASTORE2/"$2"/"$2".vmdk

if [ -f $DATASTORE/"$1"/"$1"_1.vmdk ]
then
vmkfstools -i $DATASTORE/"$1"/"$1"_1.vmdk $DATASTORE2/"$2"/"$2"_1.vmdk
fi

if [ -f $DATASTORE/"$1"/"$1"_2.vmdk ]
then
vmkfstools -i $DATASTORE/"$1"/"$1"_2.vmdk $DATASTORE2/"$2"/"$2"_2.vmdk
fi

So, just copy the script above, do a vi clone-drive.sh, then hit "i" and paste, then esc, then :wq  then chmod 700 clone-drive.sh

To Execute: clone-drive.sh name-of-source-vm name-of-target-vm source-datastore target-datastore

Then, just create a new (Custom) virtual machine in the GUI with the same NIC's, etc, and attach the new hard drive(s) you just cloned to it while creating it (you should use the same name as the name-of-target-vm above)

Enjoy!