I'm going to Washington DC next week and I'll try to update this blog while I'm there. Here's a few cards I've seen that make me think that Hausmädchen were the best "catches" for German soldiers in the early 1900s. It might be that the women had jobs and were hired because they were young, pretty, and respectable. The theme shows up in British and French illustrations as well. There's weener humor as well in some.
I wonder if it was a class thing?