To the credit of American Girl, a division of Mattel (though you'd never know it by the brand or price-point), the company has introduced a doll without hair. According to AG's Facebook page, it's part of the My American Girl line (known popularly as the "Just Like Me" dolls) and it's been designed "for girls affected by cancer, alopecia, or any medical condition causing hair loss."
In reality, many kids buy Just Like Me dolls that don't look just like the owner - but rather, look just like the buyer would prefers her or his doll to look. Lots of kids might want to own this doll.
But as evidence of the complexity of marketing this doll, and perhaps aware that some people would prefer their kids not to see or think about such things as "cancer, alopecia or any medical condition causing hair loss", Mattel is making the doll available only by phone. You can find it listed on the website - but not under the rest of the MyAmerican Girl line. Instead, it's buried in the Doll Hospital section, under Doll Hospital Services.
I think this is a shame. One of the profound challenges of being a girl without hair is the social stigma. In addition to potential profits, AG has presumably created this doll in part to provide a positive message to such girls: its OK to be you. (And if it hasn't done this for altruistic reasons, its done so because of pressure and the desire for good press.)
But it would be even more OK if the bald doll lived on the web in the midst of the other Just Like You dolls. Yes, this might cause some parents to have conversations with their children about the bald doll - but these are a good thing generally, and needn't implicate issues of mortality.
Kudos to Mattel but consider me one vote for mainstreaming the new bald American Girl doll.