A few of the companies are offering drop shipping. What that means is, if I don't have a yarn in stock, but I have an account with the company, then you can place the order with me, and they will ship it directly to you. The yarn doesn't have to be one that I regularly stock either.
Berroco, which also includes Lang, Wool Addicts, Amano, and Lopi
Trendsetter Yarns, which also includes Lana Grossa, GGH, and Cardiff Cashmere. Please note, this company charges a $1 fee per skein if you do not order a full bag (bags are often 10 skeins, but not always)