Well I did ONE load of baby laundry, so that's a start. Also went to a baby store and tried on the K'Tan and the Moby and they had a baby doll (who weighed 15 lbs) so that I could estimate placement. I asked the clerk if there was something "special" about the Moby or if was just a long piece of fabric that I could make myself and he was stunned and said "no one's ever asked that before!" Like, really? It's just an overpriced piece of fabric with surged edges! Also they were selling them for $70 and whereas I like supporting local stores and all, even with some some upcharges, that was just too absurd for me to handle.
Just make sure that if you make it it's one long piece of continuous fabric (5.5-6 meters... like 6 yards? I don't know, I'm Canadian, haha). Otherwise it will have weak spots and won't be as supportive. You'll probably end up with enough fabric to make two :)