I'm a little late to this scene but I feel it's important to close this thread.
I came across this thread because I was interested to know the memory and performance implications of choosing one property over the other. The following excerpt from http://msdn.microsoft.com/msdnmag/issues/04/09/AdvancedBasics/ makes it clear.
So InnerList should be minimally better than List. I suppose a remaining option is to inherit the Array type and build the basic functionality [including dynamic resizing, i.e. vector] that I need. Fun.
Eldar