I can't say that I've ever seen this doll before, but I've recently come across a couple of descriptions of this doll on various sites. But, the descriptions are much like yours.
The best advice I can give is for you to search eBay. I'm sure you've done that, but you never know when someone is going to list this doll. Also try searching eBay.ca and any other countries that can be translated via the babelfish translator site. :D
Also, this is an active Doll Trading forum:
Doll Mama's Den with recent posts, so I'd give that a whirl.
Also another tidbit of advice is that when you search on eBay, get an advanced search going, but don't search for the doll name of Heather and exclude words like: Barbie, porcelain, rag etc.
Good Luck!