http://www.flickr.com/groups/blythe_unlimited/
It has taken several tweaks to get the pattern to my satisfaction. The picture below shows from left to right three iterations of this design. Jasmine with burgundy hair was my first attempt. Sophia in the center has better looking legs and a more defined body, but I thought she was too skinny. BleuBelle is the final iteration; her head is a bit bigger and she has a slightly fuller body. After I've proofread this pattern (that is, made a few by carefully following my own instructions) and I figure out how to link to a PDF file, I will make this pattern available here.
I also plan to create a number of outfits for this doll, an example of which is this '60's look with bell bottoms and tunic top. Since I don't own a Blythe, the dimensions of my doll are probably not the same, but then, this is a doll inspired by Blythe, but not meant to be a crochet copy.