It goes farther than just Virginia and Maryland, the suggested legal documents that developers’ lawyers may use is at the federal level.
SUGGESTED LEAGAL DOCUMENTS FOR PLANNED-UNIT DEVELOPMENTS
28 pages  459 KB
FHA Form 1400, VA Form 26-8200, Rev. October 1973.

“These legal documents for planned-unit developments were prepared by the Federal Housing Administration and the Veterans Administration for nationwide use.”