Skimming through, need to read in more detail later, but what I would love to see is a real world comparison against just linear search in a vector. Either of associated pairs, or two vectors (one for key, one for value, with matching offsets).
My hunch is that people in general are more often than not reaching for hash-tables (and sometimes trees) for the API convenience of an associative structure -- but that on modern architectures with decent cache sizes and for small(ish) data sets they can be outperformed by a simple O(N) lookup.
For example, it would be an interesting experiment to take something like the Python runtime (or the JDK etc) and replace its dictionary type with vectors -- at least for small dictionaries -- and then run through some common applications and frameworks and see what impact this has.