Fan probably could be moved back further in the case, or replaced with a thinner ( though more expensive) one and this would improve airflow. Shielding cover, even a flexible copper foil card covered one, on the power supply would be a nice thing, would probably get half of the noise in the open input channels down. Wonder how much the noise would drop if you simply used 4 terminators on the inputs and looked again. Would have been even nicer if they had conformed to the IEC spec on the earth wire connector, blue is not the right colour for a PE conductor, it should be a green/yellow striped one. But then, a good looking PSU, good components and a fairly good layout, though they could have put in the fuse as well, not just leave it down to a necked trace to be the fuse.
As to making it VESA mountable, just buy a VESA mount kit ( the cheap one for TV sets with thin steel arms) and modify the spider bracket to fit the scope back and attach permanently, though you will need to drill the 4 holes to fit it. Otherwise just a flat old TV stand and cut it down to sit the scope on it.