Nate wroteI also don't see anything related to Spine in the cocos2d 3.0 codebase. Currently spine-cocos2d-iphone is only for v2. I do plan to update it to v3, just have tons to do.
Spine in cocos2d-x V3 is located in the /cocos2d-x/cocos/editor-support/spine folder.
btw. they still have the following in spine-cocos2dx.cpp which don't know why they keep doing despite updating code base to be v3 compatibility...
void _spAtlasPage_createTexture (spAtlasPage* self, const char* path) {
Texture2D* texture = Director::getInstance()->getTextureCache()->addImage(path);
TextureAtlas* textureAtlas = TextureAtlas::createWithTexture(texture, 4);
textureAtlas->retain();
self->rendererObject = textureAtlas;
// Using getContentSize to make it supports the strategy of loading resources in cocos2d-x.
// self->width = texture->getPixelsWide();
// self->height = texture->getPixelsHigh();
self->width = texture->getContentSize().width;
self->height = texture->getContentSize().height;
}