Twice, actually. I will dig up some pictures to post here. I submitted a couple types of walls and new posts to allow making some brick buildings in The Garden, to go with the City tiles.
I'm thinking I might even tackle a new set of roofs (not an easy task!) for this, really competing the set.
Update - here is a picture of the type of wall you can expect:
There are options for interior only walls, interior/exterior walls, walls with just the door, just the windows, just some crosses, or a door with those features. Here's another wall picture I had lying around:
I actually submitted the crosses filled in in black. If you want them cut out, just do it after gluing the wall together. I did a set of regular posts for the walls, too. That allows the interior parts of the wall to look normal, since the standard Garden set only has exterior textures.
Fingers are crossed that this will be accepted soon, along with the city tiles.