Of the Colts I've played one green in particular comes to mind - the 10th at sandy, heathy Whittington Heath GC, NE of Birmingham, UK.
Here the 10th green slopes downwards from front-to-rear, massively so.
There are numerous fine green complexes at Whittington including several with significant front-to-rear downslopes, eg the 11th, 12th, 13th, 14th and 16th, but the 10th takes the biscuit, pure evil, even more so when set up for competition play.
I've not (yet) played, for example, any of the celebrated Colt classics west of London, but were front-to-rear downslope greens a Colt speciality (I noticed quite a few of them during a recent game at his Sandwell Park too)?
Here's Sean's photo tour of Whittington Heath -
http://www.golfclubatlas.com/forum/index.php/topic,35648.0.htmlplus a Bing Sat-map extract of the course -
http://binged.it/1vnTcwnatb