Beth,
I 'm an engineer by trade and an experimenter at heart. Perhaps that is why I like beekeeping so much, plenty of experimenting options.
I never did like the fact that my hives always had moldy outer frames in the spring, and attributed it to poor ventilation. So in an attempt to find a better mouse trap, I ended up buying a
modification kit from David Eyre (
www.beeworks.com) since one of his main points in developing the D.E. hive was to improve ventilation. One of the things the modification kit did was rotate the hive 90 degrees. I don't know how much this aided in the ventilation, but I definitely noticed a difference in bee demeanor when working the hive. With the normal Langstroth, you end up working from the side of the hive and are visible to the front of the hive and the bees go on alert when they see you moving around. With the hive rotated 90, you work from the back and are undetected.
I kind of liked it, since some of my hives sit side by side, it is impossible to work from the side and I was always struggling trying to manipulate from the back anyway. I think it comes down to person preference. Like my dad always says " If everyone liked vanilla, they wouldn't make chocolate". One thing that I have changed in David's design is the bottom board. David believes in a solid bottom board with a dead air space below. I have elected to go with a SBB with a wood drawer to use for mite drop measurements and for winter closure.
I have also seen the double wide hive that you explained, but my concern with that is with the bee movement to stores in the winter, I think it is more natural for the bees to progress upward than to move sideways. Not to mention the extra details needed to make the half cover and prevent them from leaking. I felt the potential gain was not worth the effort.
If you are looking for something to experiment with on your current hives, you might want to consider Housel positioning. It basically has to do with how your combs are installed. If you look closely at your foundation, you will notice a 'Y' in the bottom of the cell. One side of the foundation has a 'Y' and the other has and inverted (upside down) Y. From studying feral bees, it has been observed that the inverted side tends to face the center of the hive. Here is a link with the details.
http://www.beekeeping.com/articles/us/housel_positioning.htmI plan on giving it a try this year (once it is warm enough to do some major manipulations). Seems pretty easy to do, and I figure it can't hurt.
FYI... If I was just starting out, I would definitely give the
D.E. hive a shot, but since I have so much langstroth equipment it is just not feasible. I think David has some pretty good design points.
Disclaimer - I have no affiliation to David Eyre other than as a satisfied customer. Both David and his wife are very pleasant to deal with and I wouldn't hesitate recommending them. Even though they are in Canada, their prices are very competitive, if not cheaper and faster delivery than some of the US companies.
Rob....