I know that you already know a lot about chemical leavening systems, but if you are going to be looking for commercial sources of such chemical leavening systems, you mind find it helpful to have a more detailed understanding of the specific chemical leavening systems used in the General Mills/Betty Crocker mixes. So I will give you a little lesson in the chemistry of chemical leavening systems, both generally and in the specific GM context.
All of the GM mixes we have researched and you have used in the course of this thread use a double-acting baking powder. A double-acting baking powder has essentially three active components--a base and two acids. The base component is typically baking soda (bicarbonate of soda). There are other possible candidates for the base component, such as some non-sodium base components, but in the great majority of the cases, the base component is baking soda. In the presence of a liquid, the baking soda acts with the acids to produce carbon dioxide (plus water). It is this carbon dioxide that causes the mixture and final product to rise. In the case of the two acids, one is selected to work quickly with the baking soda, typically at room temperature, and the other acid is selected to work at high temperatures, as during the cooking or baking of the final product. Having both types of acids means that you don't have to rush to make the final product. For example, if you had only one acid and it was fast acting, you would have to work quickly to make the product in question before the leavening power is depleted or materially reduced. Baking powders that include a base and only one acid are called "single-acting" baking powders. These have largely been supplanted by double-acting baking powders. Also, many aluminum-based baking powders (but not the ones used by GM) have been replaced by baking powders without any aluminum.
All of the GM mixes have a leavening system that comprises baking soda, sodium aluminum phosphate, and monocalcium phosphate. The monocalcium phosphate is the fast-acting acid and the sodium aluminum phosphate (SALP) is the slow-acting acid. The amounts of the chemical leavening system in the mixes and the amounts of the three components of the chemical leavening systems are established based on the types of products to be made with the mixes. For example, the Bisquick Original Pancake and Baking Mix is intended to be used to make a wide variety of end products, including pancakes, waffles, shortcake, crusts, biscuits, and so on. Consequently, the chemical leavening system in that mix has to be able to lift the final product, no matter what it is, once a liquid (e.g., water or milk) and other ingredients are added (eggs, for example). In some cases, the user has to add more baking powder, for example, to get super puffy pancakes, or more baking soda, for example, if buttermilk, which is an acidic ingredient (called an acidulant), is added to the mixture and, as a result, increased the acidity of the mixture. I am sure that the Bisquick Buttermilk biscuit mix (with buttermilk powder) adjusts the amount of its chemical leavening system, and possibly the individual components, to make it unnecessary for the end user to add more baking powder.
On of the things that I wondered was whether GM uses an encapsulated leavening system. To answer this question, I called The Wright Group and spoke with one of its technical personnel. The Wright Group is a producer of a product called WRISE that is a combination of baking soda and SALP. The encapsulation medium is palm oil. The encapsulation serve to prevent the SALP from acting with the baking soda until baking, not before. This makes the WRISE product especially useful for take-and-bake doughs where consumers often ignore or don't follow or disabuse instructions for storing and using the take-and-bake pizza. In cases like this, the yeast can stop working. The WRISE insures that there is a rise in the pizza once baking commences, even if the yeast is gone or comatose. The person I spoke with at The Wright Group told me that he does not believe that GM uses encapsulation of its leavening system. When I asked him why he felt this was so, he said it was cost. I asked him if he thought it was likely that GM is using cornstarch in its chemical leavening systems, and he answered that he thought that such is the case. This is quite common, and if you look at your Clabber Girl ingredients list, I think you will see cornstarch as one of its ingredients. The cornstarch is used to keep the base and acids from starting to work prematurely, that is, before an end user uses the mix to make something. I was also told that the moisture in the flour(s) used in the GM mixes would be diluted by all of the other ingredients and shouldn't prematurely start the chemical activity between the baking soda and the acids.
You can read more about the WRISE product at http://www.thewrightgroup.net/images/stories/pdf/wrise/wrise_101595.pdf
. I was told that WRISE would work for the type of pizza mix application you are considering but I suspect that you would have to add a fast-acting acid. I would rather have you find a source of a chemical leavening system that is like the one used by GM. You can also read more about specific elements of chemical leavening systems at http://dwb.unl.edu/Teacher/NSF/C12/C12Links/www.cosmocel.com.mx/english/c-leave.htm