Sorry, from "...it's blades are running ESXi" I assumed you are running the hosts in a cluster.
With the free Hypervisor license your options are indeed limited. Some options besides exporting/importing are backing/restoring the VMs using e.g. Trilead's VM Explorer (which is one of the few tools which support the free Hypervisor), to use Veeam's FastSCP or to copy the VM's from the host's command line using the appropriate commands (e.g. vmkfstools for the .vmdk files)
André