There are two recognized construction methods for building with straw bales.
When the construction method was first used in this country, the prairies didn't offer typicaly stucture materials such as wood or stone. The settlers were forced to freight lumber some distance or build houses using sod blocks or dig into banks of earth to make a 'dug-out' structure. With the invention of the hay baler, the first of which were stationary equipment, the product bales offered another option for building material.
Because the straw or hay represented the material available for construction and possibly because time was of the essence, the method most often used is now referred to as LOADBEARING CONSTRUCTION. The bales are the supportive exterior walls bearing the weight of the roof. The method is quite successful, particularly when the straw bales are tied together.The loadbearing method became known as the Nebraska Style. 
There are numerous websites describing the method in detail and photographs. The loadbearing method has been addressed in the Oregon strawbale building code.
The second most prominent method of building involved timber framing. This can be as exacting and involved as pure post and beam or a simple, pole building. The bales are the infill walls between the timbers that support the roof -- a non-loadbearing method.
In the Missouri project which is the Straw Bale Home Initiative sponsored by the Top of the Ozarks RC&D, University of Missouri and HUD, either method is acceptable. Because of the potential for rain or other precipitation, the Non-loadbearing method is recommended because the bales must, under no circumstance, get wet. If the frame structure is built first, the straw supply can be stored under a roof while being added as walls.
The upper picture features a house which used the Nebraska Style. The builders deliberately left the sides mildly lumpy in their southwestern design.
The lower picture is a house using the framing style--non-loadbearing or post and beam. The post and beam frame was built with the bales being used as infill. The entire walls are smooth under the stucco.
Both are beautiful, comfortable, quiet homes.
Straw is considered the construction product of highest value because there is nothing to attract seed eaters like rodents or insects. Rice straw is highly rated. The Missouri Project had hoped ot utilize straw from fescue seed production, but that hasn't been possible yet.
The Hay House, built by artist David Brown in the East was built from hay with the builder thinking if the structure lasted him five years until he built something else he would be happy. The topic of a documentary by Jeanne Newman which is now a museum piece itself, the house lasted many more years and had other owners until it burned due to electrical problems. One of the owners, David Brown, painted pictures of the Hay House which appear to be for sale on the internet at http://www.customflix.com/Store/ShowEStore.jsp?id=230596
There are reports of an old building being disassembled in Nebraska many years after it was built to examine the materials and move them to another spot. While the workers were at dinner, the neighbors cows got into the area and ate the old construction material.
Oregon has had enough strawbale construction going on to merit development of a building code for strawbale construction. Because of seismic concerns, California promotes the non-loadbearing method and code. In the Southwest, either method has been successful. The Missouri project will use the standard building codes and the Oregon strawbale code. Following the code during initial construction makes most code requirements a matter of common sense. The actual construction costs are competitive with stick built houses of similar wall thickness and structure. Strawbale according to code is most likely not a 'free' or 'cheap' way to build. The gains come in the utility bills and other management.
In the humid midwest climate, using synthetic stucco materials is 'building-o-cide'. The stucco which is applied both inside and outside and the bales, must breathe, although this doesn't involve moisture collection or drafts. When the walls can breathe, the straw won't get wet, the stucco won't come off and the weather barrier against cold and heat will be effective for the people who live in the house. Some have asked about using Straw in the midwest, particularly Missouri. The concept has been employed quite successfully in the past and in recent years.
Successful straw bale construction of any method has solid footers with the straw high enough to avoid run off or splash of rain water and a wide overhang on the roof. The house we are planning will have a veranda all around. Big Boots and a Big Hat.
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