This. Sorta like the black-translucent plastic skins on certain 80s/90s tech gear (think the translucent GameBoys and so forth). It'd look super slick.
That, or just straight-up clear, like HD820 does with their glass backs.
Speaking of HD820, if anyone who has had a chance to listen to both of these cans recently could do a comparison (or if any HD820 owners end up picking up an E3 to compare), that'd be rad
Curious how the only two higher-end glass-having headphones I can think of quickly off-hand compare!
Oh - one other request! I haven't seen efficiency numbers quoted in writing anywhere yet (albeit I only found this thread 5 minutes ago) - would love to get an idea of how feasible it'd be to push these to ~75-80dB off a Qudelix 5K for portable use. My desktop rig is an ADI-2 DAC FS, which should be just fine I presume.