Thanks for the compliments! Actually, your Midna helmet is what got me into this hobby in the first place - My fiancee's helmet was one of the first props I ever attempted, and I used a lot of your build images as reference, so thanks!
Big Daddy is one hell of a costume. The prototype is no less a daunting task, in my opinion. I have seen some very detailed renders of that drill arm and the amount of intricacy in there is just insane. Best of luck to those looking to tackle Big Daddy and the Big Sister, and I'm glad my blog can be of help in your efforts.