How about something super simple and adjustable like this?



The little triangle is a wooden cleat that runs along the bottom to prevent slipping. The chain goes over a hook in the wall -- pass a different link over the hook for adjustable angle. You'd need two chains, possibly going to two hooks (but one would work). Finding a good way to attach the chains to the vesa mount might be tricky, though...

Sure it looks like crap, but you'd only ever see it when adjusting. smile