At Synergy, McAfee announced their new virtual endpoint security platform, called MOVE (Management for Optimized Virtual Environments). A key part of this platform, called A/V Offloading, removes the need to run an antivirus solution inside each virtual machine by offloading all the scanning and processing (real-time and on-demand) to a virtual appliance. The virtual appliance talks to lightweight agents running in each of the VMs, but all the hard works is done out-of-band. Because of this, McAfee is claiming up to a 3x improvement in VM density on a host (which I'm sure MANY people will test when the opportunity presents itself).
Frankly, this is the type of thing the world has been waiting for. I'm sure that other antivirus vendors are already working on their own similar solutions, but cheers to McAfee being the first to market with this.
In this video, McAfee's Director of Product Management in the System Security Group, Kishore Yerrapragada gives a short overview of the platform and shows a quick demo of the resource consumption of virtual machines with and without A/V Offloading turned on.