All of the features of the different designs can be combined to customize a kiln for your particular needs. 

New - half pint version:  Many requests have come in for a smaller kiln.  A two room version is now included.  This kiln will dry about 4,000 bf/yr. 

Suggestions from around the country that you might be interested in:
Stephen Taylor of Vermont Family Forests redesigned the kiln as part of a small sawmill building.  Two kiln chambers were built inside the building, with the south facing roof being used as the collector.  Combining the two buildings saves space and money!
Another design alternative from Vermont is to extend the back storage area of the wide version to make more usable space for pre-drying, sawmilling, or equipment storage.  A little more roofing material can make a lot more usable space.
Stephen also quotes an article by Dennis Scanlin in Home Power Magazine #63 about the Appalachian Solar Lumber Kiln.    Students from Appalachian State University used multiple layers of dark colored aluminum window screen as their collector surface.  6 layers absorb the sun's energy and transfer the heat as the air flows through the layers of screen.    Hi tech stuff!  Stephen has other ideas for glazing also.
Photovoltaic panels generate the electricity to run the fans.
Stephen Taylor can be reached at (820) 453-5916 in Lincoln VT

Jim Beeman of Hiawatha Sustainable Woods Cooperative in Fountain City, WI suggested dedicated insulated chambers to save money.  He built a special rack next to the sawmill to aid in stickering the lumber right off the saw.  The bundles are moved by fork lift to a pre-drying location.  When a kiln charge is dry, the fork lift unloads the kiln quickly and places stacks of pre-dryed lumber back into the same rooms.  This is great if you have flat land and large fork-lifts!  It would save on construction costs by reducing the amount of concrete needed for the slab, less insulation needed for chambers, permanent duct systems, and only one door is needed.  Jim can be reached at (608) 687-8193.

Introducing:  The Timbergreen Super Solar Cycle Kiln
Combing all the best ideas for our next project, we have now built a kiln that is 108 feet long and 32 feet wide with 9 spaces across the front for piles of lumber.  The center three chambers have a concrete floor and insulated walls & ceilings.  The back wall of the kiln chambers are permanent and the front has sliding doors for access just from the one side.  Six separate one half horsepower fans feed a permanent air duct system into the three rooms. The stacks will be placed with a fork lift. 
The rest of the building is essentially a pole shed and will initially have a gravel floor for pre-drying lumber.  The back portion of the building will be extended to twenty feet deep to accommodate sawmill equipment and other uses.  The end walls of the building will be sheathed for strength.  This equipment should dry about 250,000 bf per year. 

The Super kiln has exceeded our expectations - this thing really cooks!  Temperatures are reaching 80 degrees above the outside air temperature on a clear day.  An additional kiln chamber to dry more wood at a time would be an option.  Improved one way valves that operate with the pressure of the circulating fans keeps the heat in the kiln chambers at night.  Weather stripping normally used on garage doors works well to seal the sliding doors.  has photos of the construction project.

New Hybrid Solar/Wood Heated Kiln    Clyde Samsel is our boiler specialist (715) 249-5602

Combine a wood fired kiln, a solar kiln, and a pre-drying chamber (or dry storage room, or a millwork shop, or a sawmill line) under one roof for maximum efficiency.  You need buildings for cover, humidity control, and heat in cold weather. Collect the free solar energy from the roof areas and south facing walls of your buildings to assist the heating.  Burn your wood waste to heat kilns, workshops, warehouse, store, office, and sawmill line.  This Hybrid is flexible, controllable, energy efficient, environmentally friendly, and did I mention - renewable.