I strongly advise checking the size of the screw-heads used to attach the RPi to the hex-standoff posts.The screws I received with the BrickPi B+ case (the ones with a built in flange) are too big for the spaces on the B+ (and probably the A+), enough that screwing them in will damage components in two of the four possible locations. Both of the problem locations are on the same side of the B+ (the HDMI side), so there is no safe way to attach the Pi to the case because neither diagonal is viable.
I solved the problem with a set of metal hex-standoff posts from Radio Shack. The stand-offs are of a useless size for the BrickPi, but the screws that come with the set are perfect, and the set was cheap enough.
Attached is a picture of the problem screws.
P.S. In addition to slimmer screws, it would be nice if the cases came with four hex stand-offs.