Maya Wrap also makes kidslings. If you want to make one they are pretty easy for a simple one.
Go to a fabric store and in thier odds and ends section you should be able tofind rings get some good think ones or metal.
Forl ittle kids (up to four) 1/3 yd of faric is enough. For older kids get a yard, cut in half and sew ends together to make it 18" wide and 108" long. Wrap aound and trim end untill it is the desired length.
For a maya wrap style sling sew a 1/ inch him around edge or serge. Fan fold end a slide rings on. fold fabric over about an inch and sew. DOne, just thread other end through rings and adjust.
For OTSBH style: Sew ends with 1/4" hem. fold fabric ove 1" to make casing and sew at bottom. fan fold ends and thread though rings. sew closed. Stuff poly-fil or dotton batting into casing to make the rails. Fan fold end and sew in long streight lines up to 4-6 incjes to make tail or leave unsewn (it is a doll sling. if the baby falls out no ne will sue you) Thread ends through loops ta-da.