I bought one similar for my daughter and thought it would be simple to recreate one for my niece. Inspired by the Mei Tai look I made a mish-mash. Now, I will say if you have the fabric laying around and all you need to buy is the hardware and straps this project is economic, but if you go crazy with the fabric you might as well save your time and buy it made. I spent ten dollars for the hardware and strapping.
2 yards of Backpack strap
(2) packages of "Center release buckles" (I am using this one cause it is easier for my 2 year old daughter to operate herself, vs the one that is on her original)
(1) package of Strap Adjusters (had to go to three sores to find these)
complementary scrap fabric. All the parts don't have to match or do and but be creativeThe backpack strap cut as follows:
(1) 4" for female waist buckle
(1) 13.5" for male waist buckle
(2) 4" for strap adjusters
(2) 15.5 or so for the shoulder strap
(2) 4.5" for the male and female chest bucklesI took one 11x12 and cut a 7x7 square in the center and finished the edges and sewed it on top of another 11x12.
I then sewed the straps closed with the strapping in the nose so when you turn it, it is on the outside, place the batting in now or when you turn it. Top stitch down the center. Top stitch the edges and sew an X over the strapping, see photos. Sew with an X the strapping and chest buckles about 3.5" (to center of strapping) up the shoulder from nose. See photo above for angle.
Do the same as above with the waist band leaving the top open for turning and sewing in the 11x12 sandwich.
Sew the shoulder straps angled down to the top corners of the front panel. Sandwich the outside panel and the inside panel with the baby pocket, turn. To make sure I got them in right and straight, I opened the seam just below the top of the baby pocket, inserted the strap adjusters and top stitched with an X.
Insert 11x12 panel to the waist band, top stitch close.
Finish ends for straps so they don't fray, or slide out of the fasteners.