Interesting. Have you considered trying with some of the battery-powered portable solutions? Not all output USB, but some (eg the phones) do. Maybe pair them with a regen or ipurifier or iusb and we're still looking at much less than some of these.
Look at the AK500n. It includes a BIG battery inside that isolate it from the pollution of the Main, and which also allow 7 hours of operation away from the main (you can enjoy it at the end of your garden...). Up to 4 Tb od SSD !
I listened to it twice for few hours in calm situation, connected to my EC445 tube Amp, comparing it's internal DAC to my HUGO. It sounded good, but I could not connect it to a TOL external DAC since I only had a HUGO available. I found it's internal DAC more musical than my HUGO, but may be less analytial.
It has many digital & analog outputs but... lack USB output !?