I was looking at those cheap USB DVD drives as a means to then play CD's, or turn into FLAC files. They aren't super expensive and can be put away when not in use. Although that one from JL looks lovely. I do like the look of Fiio's DM13 and would match the R13 R2R in looks.
I haven't heard Warmer of course, which I imagine does something similar, but certainly with the old fashioned high impedance headphones like the 6x0, or DT 880 the extra resistance and distortion plays lovely.
Personally because I don't use the TA-66 all the time the tubes will last ages. But also where you aren't buying matched tubes, or even more exotic tubes the prices for new tubes can be cheap. But I appreciate that isn't always true and where you get into this 'not-entry' level price range for tube amp things get expensive quickly. Mind you when the 6x0/880 sounds this good on a budget OTL I still wonder what it would sound like on something more premium.