It seems like shopkeepers are extremely weak (slightly stronger than a normal villager), and I cannot seem to purchase anything (I thought I read somewhere that you (c)hat to them to buy stuff, but I only get the same "[#don]'t respond" message). Also, it seems that items in a shop can be generated on the shop door as well as the ground right inside the door:

. . @. T
##*##
#**@.

I suck at the whole "one bug per report" thing.