This is all I could come up with from a Goggle search.

Henry Rieff, a well known Fayetteville merchant. According to the Book Fayetteville Arkansas in the Civil War by Russell L. Mahan, copyright 2003 page 19, Henry Rieff was appointed Colonel of the 20th Regiment of the Arkansas Militia and raised a militia company in Fayetteville called "The Washington Rifle Guards".
http://sites.google.com/site/arcurrency/arcurrency/washington-county

Arkansas Militia in the Civil War
http://uk.ask.com/wiki/Arkansas_Militia_in_the_Civil_War

http://wpedia.goo.ne.jp/enwiki/Arkansas_Army_National_Guard

http://en.wikipedia.org/wiki/User:Damon.cluck/Arkansas_State_Militia,_1836-1876