Man thats impressive!
My question for you is, do you use all these in a normal 40k game, or do they join battles in Apocalypse only?
Why I ask is because Imperial Knights are really powerful, and I can't really see many normal 40k armies tearing them down. The one thing I can see is locking them in close combat with some less important units.
I've used up to 3 Knights, with Vets and Gunships in 2K games:
+ Space Wolves Arjac and Shield Brothers once killed all 3 Knights over 3 consecutive turns
+ Also I always lose all Knights and Gunships to Tyranid Flying Circus equipped with Haywire
+ I've also had Orks tarpit my Knights for 2 / 3 turns
The thing is, Knights are devastating if your opponent isn't expecting them but I use them so much that my regular playing buddies have become so good at taking them down fast.
See the Storm Trooper battle summary link in my sig - I have a short write up somewhere in that thread with 2 Knights and Scions vs Deldar. I lost.