I second this. Most of the real practical techniques in TKD are found in the patterns. It is just about looking in the right places. I'm surprised that we don't get taught them explicitly. Patterns are much more than just dances,especially the higher belt patterns. That said, I still don't think it's enough to defend against a grappler without cross training.
I second this too! I spent 4 years on Tang Soo Do, have an superb application to Chil Sung Ee Ro Hyung - including arm bars, groundwork and neck wrenches etc PM me you email if you known this Hyung and I'll send you the details.
I'm working through Koryo Poomsae at present and I will give everyone details of what I found and I think get it on YouTube for you all to see!