I combined the ease and supportiveness of a structured buckle waist with mei tai straps with this hybrid.
I found I was using my Ergo more and more because I like the supportiveness of the structured waist. There are some drawbacks, however. I can never get the chest strap where I want it in a front carry and it's a pain to adjust the shoulder strap buckles. Enter MT straps with a structured waist DIY! Now I have the supportive waist plus the adjustability of tied straps. The straps are a chocolate brown canvas and I backed it with chocolate brown baby cord. The body also has an inside layer of canvas and is padded with one layer of cotton batting. I added seat darts as well. The structured waist was made with one layer of high density foam cut from a camping mat. The mat was around $6 at Wal-Mart and I probably have enough to make 5 or 6 more.
Can I just say this thing is amazing! It really hugs my babies in close and literally I feel nothing on my shoulders in a back carry. It's like they are glued to my back. I think this is because the straps also provide a lot of support when they are twisted or crossed at the baby's back: something a traditional SSC lacks.
Sorry I don't have time for a tutorial right now, but if you can make a MT, this really isn't that much different. The waist takes a little bit of time, but if you already own an SSC you can study it to see how the waist band is sewn and attached and replicate it.