Here is link #1:
/post/79372/
Here is link #2:
/post/111475/
look at the very bottom of the message
There are more maps than just those labeled "S," but around 10 of them are playable within 2-3 hours.
P.S. In general, considering the latest trends in Heroes online, many people play random games – using specific templates... they are always different and generate quite well. You just need to choose either a large map with a basement ("L+U") or an extra-large map without a basement ("XL"). However, on average, a game lasts about one month.
This file is at the end of the message (see link #3):
/post/127898/
And by the way, this message contains reasonably good rules for the game.