I agree with you it'd be useful to see how you might implement lambdas in a language like C. But after that first example, implementing other more complicated language constructs in C, instead of learning ML/haskell is going to be more time fighting C, and less time learning anything new. The lack of side-effects and equational reasoning in functional languages let you get a lot of details out of your way.

That being said, this is if you're interested in the theory. If you're interested in building compilers, this list won't help too much.