I have a jazsling that I use only for hip carries when DS1 was younger. It was good in that the fabric spread out the weight over your whole shoulder area. But DS was probably 9-10kg when I was carrying him like this. Also the jazsling is sized and now I am a bit bigger it doesn't fit as well. Sorry, probably not very useful!

I am thinking of buying a Beco gemini which can do a hip carry, but not cheap.