Wouldn't exporting to an OVF export to the local machine and therefore require the vmdk to be downloaded from the ESXi host and then require it to be uploaded again?
Why not clone the base VM to create a new VM. Right click on the VM and select Clone, oh hang on that needs vCenter also think.
Best bet would be to upload the vmdk once to a folder called say Template and then use vmkfstools at the command line to copy the vmdk to a new folder for each VM required.
What happens if you browse the datastore from the vSphere Client and copy the vmdk file and paste it into a new folder? Does the client do the work, i.e. the data comes from the host down to the client and back up again?