Apply shaders to Emulationstation itself?

[Cannikin]

Anyone know if it's possible to have a shader applied to Emulationstation (the interface where you choose your emulator and game) itself, in addition to the emulators?

I'm working on an enclosure for my screen that'll crop it to match the pi-curvature shader:

But when not in a game the ES interface will be hidden behind the edges. Ideally I could apply the same shader to ES itself and then everything will be a-ok. Any ideas?

[Cannikin]

There are a couple of themes which would work with this frame, like crt-centered:

But it would still be nice if the theme had the matching shader applied for the scanline/pixel smoothing effects...