The Straight Dope isn’t exactly kid friendly. If AOL was still hosting us, we’d be pretty much invisible to anyone under 13.
Mablache,
The Straight Dope has always been a little on the PG-13 side. All sorts of questions of various adult related topics have been asked about on this site. I’m sure there are other sites out there that would be more appropriate for children.
MJL
I agree Ice Wolf, I think the only time I’ve heard that exact phrase used is in respect to Rugby forwards. 
On the other hand, I have heard the phrase “built like a brick battleship” used to describe an extremely robust and well-built woman… of the Wagnerian soprano / valkyrie type.
Here in the UK, “built like a brick shithouse” is ONLY ever used to describe men. You would refer to someone being " built like a brick shithouse" if they were muscular.
Would never dream of using the pharse to refer to women, it could land you in a spot of troubel over here in the UK !!!
I grew up in Wisconsin and I heard this phrase frequently from my pre-teen years onward.
It was always specifically used in reference to very large breasts carried proudly. Even a woman with a terrific figure with moderately large breasts would not usually be referred to this way. They had to be overly large. It was always an incredulous comment along the lines of “oh my God, would you look at those!!”
Of course, if they were pendulous (hangy-downy in our teenage venacular) we’d just gag rather than be impressed.
t-bonham’s explanation of being “over built for its intended purpose” is a good one. However, our usage was not that intellectual. It was simply an expression of appreciative amazement. Similar, I suppose, to the amazement we’d have felt upon seeing a brick shithouse.
Apropos of absolutely nothing except that it popped into my head while reading the column and this thread, in the movie Stalag 17 one of the POWs referred to one of the female Russian prisoners as being “built like a brick Kremlin.”
I heard the simile often in my teenage years, and just a few years ago I saw a real brick shithouse. Then I understood, and I nearly drove off the road laughing. It was nicely put together, with pilasters at the corners, and a little + figure in the middle of each side. It was a lot of the bricklayer’s art put into a little house that was useless after the dung hole was full. In other words, it was built much better than it had to be. In terms of a woman, there’s a level of prettiness that will cause a man to say to himself, “Hey, she’s pretty.” There’s a whole 'nother level that causes the same man to stop in his tracks and whisper something about divine dung (If he speaks Arabic, it’s pronounced, “Countach!”) That woman is built much better than necessary.
Large-breasted women in the US are referred to as “built”. I suspect someone who knew that term was in the UK and heard someone say “built like a brick shithouse” and thought it was just an amplification of the term he knew, without understanding it meant almost the opposite - a large muscly bloke.
My theory, FWIW.
I’m from Georgia and I’d never heard it there. I dated a girl from Mississippi for a while and she and her family used the phrase to refer to muscular, stocky men.
For those of you wondering about this phrase being used as a compliment, I don’t think this is something that would be directed at the woman in question. “My, you’re built like a brick shithouse.” Rather, it’s one of those observational asides to your comrades to draw their attention, or to describe a previous encounter to some subsequent gathering of friends.