Streamer/DAC

I think I have the computer thing figured out now, so what about an all-in-one DAC-Streamer Combo. I like the one box solution (in my case 2 boxes,  integrated amp, and as discussed).

One disadvantage is that I presume that there is not much chance of upgrading the DAC in a combo like this, so as technology changes you with miss the buss or fork out for new.

Any streamer/DAC combos that you've heard that you could live with forever for around $4K? I know mrklas likes his Moon 280D which is attractively priced.

With the popularity of R2R DACs are there any offered combined with a streamer?