I can't find what I'm looking for. I just want a digital transport. That's it. I do NOT stream music, and I don't need a built-in DAC, preamp, amp, or any other crap normally associated with streamers. I don't even need to attach a hard drive; a USB stick is good enough. It can't get any simpler than that. The digital transport I want should have proprietary software and a high-quality clock. I've tried the free versions of Volumio and Moode, but they're inconsistent. I've also used the proprietary software from Lumin and Eversolo, and they're 10x more stable than the free stuff.
My question is -- does anything like this exist? I'm willing to consider DIY.