Keep an eye on the following site: http://www.flickr.com/groups/civil_war_veterans_kansas/
This is the Civil war Veterans Buried in Kansas group on Flickr (formerly Yahoo Photos). Mr. Wayne Turner who lives in El Dorado, Kansas already has a photo of your ancestor's gravestone and is only waiting for his film to be developed. He should be posting it on the site within days. Mr. Turner has done extensive research on Civil war Veterans of Butler County, Kansas and might have additional information on this gentleman.