I have made most of my own dessert buildings for my 15mm stuff but also grabbed a few of the Gamecraft ones to quickly swell the ranks and relieve the bordom of cutting out doors and windows for hours at a time.
Have you not considered making your own, they are very easy to do once you decide on the height of a single floor building.
You can see some of them here:
http://ambushalleygames.com/forum/viewtopic.php?f=8&t=6632and I can send you the sizes if you want to give them a go?
Jim