R-2R for HQ sound output
You need to consider the accuracy of the resistors required to implement a R-2R ladder.  Even .1% as you mention is only 1 part in 1000, or good for about 10 bits.  If you implement a wider ladder with these resistors, the additional codes will be scattered around and not monotonic.

It is a lot easier to match and trim resistors on a single chip, which is how they can achieve 16 bits at reasonable cost.  I haven't looked, but it surprises me that audio frequency 16 bit DACs cost $20.  My knee jerk reaction is that's too high.  It also doesn't make sense that getting such a part takes 2-4 weeks.

I saw a technique once that used a bunch more bits in a R-2R ladder than the resistor tolerance could support.  In fact it wasn't exactly 2x between the resistors so that the resulting voltages would be more evenly scattered.  This guy then measured the result of every last code accurately, and found the subset that gave the desired response for the number of bits he actually wanted.  The output value then went thru a lookup table before driving the R-2R ladder.  Of course if temperature drifts a bit, the mapping is no longer valid.