Amazingly enough, http://www.retro.live has a working implementation of XBAND. You can see a demo of it in the excellent Wrestling With Gaming documentary on XBAND: https://youtu.be/k_5M-z_RUKA?t=3448
Even cooler that it works on Analogue Super NT. That's two layers of video game history preservation right there :) After all, eventually, some day, the last working SNES unit will fail...
I don't see very much information on retro.live's page, but I hope they heed the lesson of Xband's demise and open source the important bits of their work in some time.