Greg stumbled upon this site this morning and it looks very interesting. A bit fancy for my tastes, but if you want a beautiful hive, then this might be right up your alley.
For the record, the site’s claim that topbar hives “fail(s) to meet USDA regulatory inspection guidelines” is utter nonsense. Topbars are easily removed for inspection, it just may take a bit of education for your local bee inspector. Also, as near as I can tell, the USDA has no regulations regarding hive construction. Bees & hives are mostly regulated at the State level.
Speaking form experience here in Ontario, the inspectors are more than willing to work with you on whatever type of equipment you have. As long as the combs can be removed for a look, they don’t care what kind of equipment you have.