In general, the rooms on the concierge level are the same size as the rooms on the lower levels. Some have a king bed instead of two queen beds (e.g. Contemporary).
At the moment, I can't find the link , but there is a site that has room layouts for all (or most of) the resorts, including suites. If I find it later, I will post.
It's been my experience the Polynesian rooms are just a bit larger than the other deluxe resorts. The concierge rooms at the deluxe resorts are no larger than a standard room (unless you're talking about suites). In fact, I think the rooms in Tahiti at Polynesian may be just a tad larger (mostly in the bathroom area).
The room size at a deluxe resort is larger than a moderate which is larger than a value.
Other than suites, AKL has two sized rooms, Standard and Deluxe. These are all throughout both standard view, pool view and Savanahh view. All concierge rooms are Deluxe size.
Boardwalk Inn have deluxe concierge rooms available which are 644 sq ft as opposed to the regular concierge rooms which are 434 sq ft. These rooms have an additional seating area which has a queen sized sofa bed in it as well as a tv/vcr. It is not a suite as such as it is not separate from the bedroom. I think they run @ $50 / night more than the regular concierge.
At the Poly, Tahiti, Rapa Nui, and Tokalau are the newer buildings and the rooms are somewhat larger than the older buildings. Concierge rooms are in Hawaii..therefore a little smaller than the rooms in the newest buildings. They are still spacious, however.