Take a look in the Rohbau section -> Architekt/Architektur ( ), there were also a few other topics where people in Munich or the surrounding area were looking for architects. Not many names are generally mentioned, but maybe you'll find something relevant for you. However, I don't know who among those who already have experience is still active if you have any inquiries.
My feeling is that there are some experience reports here in the forum about the big GUs, but for single trades or regional providers in general, you have to be a bit lucky to find anything.