I transcribed the Index of Names (Namenverzeichnis) for the Roll of Officers (Rangliste) for the German Army in 1927 and created two FREE pdf files that are available through Lulu.com:
http://www.lulu.com/shop/search.ep?type=&keyWords=Reichs...=
I've had to modify the format a little, but it follows to the original in only listing surnames, as well as only providing ranks only when there is more than one officer of the same name.