A new open source USB-MIDI controller called the aurora mixer looks really nice. The creators are trying to figure out how many to make and how much to sell the assembled version of it so if you think you might be interested definitely give them a ping.
If you think you might have it in you to build your own then you’re in luck because according to CDM the whole project is licensed under Creative Commons — although that isn’t mentioned anywhere on the aurora site and, well, there’s no mention anywhere as to which license we are talking about it. The other weird note is CDM’s comment that GPL is more “liberal” than CC and therefore we are seeing more CC licenses come up in the music industry. My guess is that it will take somewhere between 10 years and never for the public to figure out that CC is a hardly a single license but a family of licenses with a very, very wide range of (un)reserved rights.