I applaud your interest in using wheatboard for your cabinets. Wheatboard is similar to particle board in that it is composed of small fibers glued together to make a larger board. It is made from straw, the stalk of a cereal plant after the grain or seed has been removed. Recycling this unwanted agricultural byproduct into building materials increases the useful yield from the crop, and reduces the pollution created when it is burned to clear the fields.
It is difficult, if not impossible, to find pre-manufactured, unfinished wheatboard cabinets. There are several cabinet lines, such as Humabuilt Wheatcore and AlterECO's WheatGrass series, that use wheatboard or wheatgrass as a substrate, with various wood veneers.
In order to achieve your goal of finishing the cabinets yourselves, I suggest that you have custom wheatboard cabinets fabricated by a local cabinetmaker. Two L.A.-area cabinetmakers I recommend are Colin Le Gallez of Functional Art (310-328-5281), who has worked with wheatboard, and Caleb Powell of Paragon Cabinet West (323-356-7189), who is interested in working with it.
When specifying the wheatboard to be used, consider emission-free products that use a formaldehyde-free binder or exert high pressure and temperatures to force the straw to release a natural resin that binds the fibers together. Environ Biocomposites manufactures several lines of panels made from agricultural byproducts, including BIOFIBER (made from wheat straw) and Dakota Burl (made from sunflower seed hulls). These products are formaldehyde-free, and no out-gassing solvents are used in their production. The company is based in the Midwest, close to the material source. Kirei USA offers a beautiful board with no added glue that has a lovely grain when treated with a clear sealer. Unfortunately, the product is manufactured in China, so there is quite a bit of shipping involved with using the board.
California residents should keep an eye open for agriboard panels made from California rice straw, coming to the market soon. Watch the website for the California Rice Commission for more information.
Be sure to discuss fabrication methods with the cabinetmakers. They should select low-VOC glues or, better yet, use mechanical fastening methods to hold the panels together.
As for finishing your new cabinets, you can use a sealer or a penetrating oil finish. If you are interested in a sealer, consider AFM Safecoat Durostain, a semi-transparent stain with very low VOC content. An alternative is Osmo, a line of solvent-free finishes that contain no biocides or preservatives. Both of these products are available through Livingreen in Culver City, among other outlets.
If you are interested in an oil finish, consider tung oil, a renewable resource extracted from the nut of the tung tree. Chinese merchants used tung oil back in the 14th century to waterproof and protect wooden ships. Many products today combine tung oil with other ingredients like resins or mineral spirits to improve wearability. However, these ingredients may increase the VOC levels of the product, so be sure to read the label carefully.
For more information:
Susan Davis's "Can You Offer Advice for Building Our Kitchen Cabinets Sustainably?" is another professional's take on green cabinets.
"Getting Great Green Results from a Cabinet Shop" gives tips on working with custom cabinetmakers.