PLEASE NOTE: This post is NOT meant to be a serious suggestion - just the product of a tired and idle brain mucking around! See my comment below for details.
Mrs D is full-term and about fit to pop with Child, Infant, No. 2, Changing for the use of, and I've noticed with not a little dismay that not only have I had practically no hobby time in the last month, I've also been neglecting the blogosphere both passively and actively. So here are some thoughts about something whose absence is conspicuous in the 41st Millennium...
So why don't we ever see them in 40K?
'But Drax,' I hear you cry, 'Many fortifications have a dry moat!' And you're right, of course.
But think about how they often work practically: the best one are comically deep and some of them even have my favourite features: caponiers and counterscarp batteries (or counterscarp loopholes), so that once the enemy are in your dry ditch you can absolutely rake them with enfilading and counterscarp fire. I'm not saying this is flawless, but it's a hell of a lot better than just plonking your fort down somewhere flat...