54mms come in PIECES! You can buy sprues of heads, hands, weapons, etc., etc. And you can get not only generics, but ARMATURES [= skeletons], some of which can actually POSE a bit! And some of them are in RESIN, a material I actually like working with much better than vinyl/ABS/action figure plastic! This means that I can make SOMEWHAT POSEABLE DOLLS FOR MY DOLLS WITH VARYING BODY TYPES, FIBER HAIR AND REALLY SIMPLE FABRIC OUTFITS!
I am so excited about this! I’ve wanted articulated ~1:6 scale dolls for my 1:6ers for YEARS!
JMD Miniatures provides a 3-pack of articulated armatures without heads or hands. They appear to be guy bases, but I don’t really care. They also have two sets of 5 heads and 6 pairs of hands apiece, but, irritatingly enough, all the heads are for dudes.
Historex Agents makes a 5-pack of female heads with sculpted hair. They also have a wonderful series of 5-packs of "expressive heads," again, all for dudes, but more versatile than JMD Miniatures’ because there’s no facial hair. On this page, they’ve also got hairless heads and massive packages of hands.
EDIT: Wonder if I could buy heads and hands and make my own damn armatures?
EDIT 2: Red Lancers has some Historex heads and hand sets. And they’re a US dealer!
Colorado Miniatures, also a US dealer, has Hornet head sets and hand sets. The "African" and "East Asian" head sets are pretty neat. There’s a "Female" set too that frankly has nothing to distinguish it from the "male" sets.