The Uniform Guardianship, Conservatorship, and Other Protective Arrangements Act (UGCOPAA) of 2017 is the model guardianship statute produced by the Uniform Law Commission.
The UGCOPAA includes provisions promoting SDM as an alternative to guardianship. (See, e.g., UGCOPAA, Sec. 301(a)(1)(A))
Link includes list of states that have adopted the model statute.