Nope this has not been added yet.
It is usable but the positioning is kinda naive.
If the FiiO devs can be pursuaded into modifying the rendering region, I guess all of us modders will benefit greatly.
Here's an illustration:
The grey area is the region to which the rendering of the quick menu images is currently restricted to.
We can use the entire width and height of this region but then center alignment won't be possible.
If this region is extended to the green area, we can use full size images for the quick menu just like we do with the normal menus like the main menu, categories menu, etc.
This can solve a lot of "cramped layout" related issues.
Also, I think if the entire screen can be utilized, your arc-like menu concept will flow nicely. It won't seem as if the arc appears and disappears suddenly like you said.