Stan,
If you are OK to use vCenter Server Appliance , for a small inventory size the recommended RAM provisioning is 8GB, which fulfills your requirement.
Please see the Table 2-6 in documention: http://pubs.vmware.com/vsphere-51/topic/com.vmware.ICbase/PDF/vsphere-esxi-vcenter-server-51-installation-setup-guide.pd…
--dGeorgey