Cloning will not do vmotion, its just a copy operation. While cloning it will ask for the destination host and datastore, but i dont think while doing that operation it will give you the hosts/datastore from other vcenter as this is limited to one vcenter. But still you may do the following
You have make the datastore shared on hosts from both vcenter server.
Initiate the clone operation from the source vcenter while chosing the datastore, choose the datastore which is shared across both sites. Once the clone is completed, remove the vm from inventory on the source vcenter and register in the destination vcenter ( this requires downtime)
Hope, this helps.