This is fantastic. I wonder... could you have a carpenter create a custom frame? The solar panels could slot into channel around the perimeter of the frame and look like part of a design. It would look seamless.
Just a few days ago I stumbled upon Exeger and its promising Powerfoyle material. Looks like Big E Ink is already on it: https://www.powerfoyle.com/news/exeger-and-e-ink-partner-to-...
To me, the most elegant way of re-doing the frame would be to coat the entire visible surface in this material.
I think you can even do this yourself with some woodworking skills. I wonder though if there are "nice" solar cells for DIY projects or if those "all black" panels are just for larger installations.