Well, I am not in the know .. but here is top view of a Zeus Boson model ... a.k.a. "FLIR Thermosight Pro 6-24x75 30Hz Thermal Weapon Sight with Boson 320x256"
Now if these ever actually get released - based on the pic at least - they would have focus ring ... this is the 75mm model and there is a 50mm model as well ... and though these are shown as 320 models we can continue to dream that the 640 models would not be far behind ... but it might be 1-2 years ...
These are shown as "discontinued" on the night vision guys website ... but that might just mean "pushed out" ... way out ...