If you're familiar wih the Microsoft Surface Dial, it's kind of like that, but with a higher quality build, all aluminum, RGB lighting (for volume indication), bluetooth range up to 10 meters, LiIon battery charging and over 50 hours battery life between charges.
I'd be interested to hear if this would appeal to Volumio users. I'm adding software support to both software music players, as well as hardware like receivers and speakers.
If there's enough interest from Volumio users I'd be happy to add support for it. The remote has a pushbutton built into the knob and a secondary button placed in such a way that you can do quite a lot of functions - volume, seeking, pause, mute etc should all work well.
I'll have some early production prototypes ready in about a month for beta testers (please PM me if you're interested) and hopefully the final versions shipping a few months after that.
If you're interested or have any questions I'd like to hear from you!