Oh, I have one of these.
DD1 has red hair. Bright, glowing, spun with gold and orange and blonde hair (except for her eyebrows, which are transparent, and her lashes, which are palest blonde). At the time she was little, all dolls were either blonde or brunette, with the very, very occasional concession to equality with a single black or dual heritage doll in some ranges.
When she was four, there was a special edition Barbie mermaid produced in limited numbers in the US. And it had red hair. (NB, this was years before The Little Mermaid).
Bearing in mind I was on about £125/week with £84/week in rent and council tax costs alone (no top ups for working parents at the time), I took a day off work and travelled into London, as the only shops that had them was Selfridges or Hamleys. I fought my way through the crowds because, naturally, DD's birthday was at the end of November and she only announced two days before her birthday that she'd heard of this from a friend at school who had seen them there.
The crowds were awful. The heat, the noise, the confusion, the QUEUES and I searched the racks, but couldn't find one. I nearly burst into tears when an absolutely lovely, very young sales assistant asked me was I OK and what I was looking for and, after keeping me waiting for another 35 minutes, disappeared out of sight. Then her head popped up from under another till and she had one in her hand. I then had to stump up fifty fucking quid for this thing when the standard ones were about a tenner - without crying too much out of sheer gratitude. If anybody so much as glanced at my yellow bag in the tube crush, I gave them a Death Glare.
DD was over the moon when she opened it, played with it loads - but she'll never know the ridiculous lengths I went to so she could have a doll that looked like her.
These days, you just type it into Google/Amazon/whatever and you'll find any type of Barbie you want. But all that time, effort and shitload of money went on one Mermaid Barbie that spent its time without her tail (because it was usually sat on the stupid cat's back) as she played with it until she was eight.
Totally ridiculous. But totally worth it.