When I saw the throwdown segment, I too couldn't help but notice the light coloration of the Malnati's crust. That prompted me to take a look at the Malnati's dough ingredients as I posted them recently at Reply 2 at http://www.pizzamaking.com/forum/index.php/topic,7467.msg64252.html#msg64252
. As can be seen there, there is neither sugar nor salt in the Malnati dough. The lack of sugar means that the crust coloration has to come from the type of flour used (I am assuming that the flour is all-purpose flour) and the amount of residual sugar in the dough at the time of baking. There are some simple sugars in the flour that get used up fairly quickly by the yeast during fermentation but the bulk of the sugar that ends up as residual sugar comes from the action of enzymes to convert damaged starch to simple sugars. That usually takes a fair amount of time to happen.
The lack of salt is also a contributing factor to final crust color. As is well known, salt regulates the fermentation process by its effect on yeast. In the absence of salt, the yeast can ferment without restraint. This means that the yeast can work even faster to consume sugars in the dough. The net effect is that the residual sugars in the dough at the time of baking may be low and result in a light colored crust. For those who are interested, this aspect of the effect of salt on crust coloration is discussed at http://www.kingarthurflour.com/professional/salt.html
Unfortunately, the above analysis does not tell us how Malnati's prepares and manages their dough. I can think of at least three ways to get the light colored crust. One way, for example, is to use a lot of yeast and a room temperature fermentation covering only a few hours. During that time, there will not be a lot of residual sugar in the dough (the time is too short to yield higher sugar levels) and the finished crust is very likely to be on the light side in terms of crust coloration. A second way is to use a small amount of yeast and a considerably longer room temperature fermentation. This is a harder process to manage because of variations in room temperature (seasonally and even intra-day) but should allow for more sugar from conversion from starch to feed the yeast. If that sugar is promptly consumed by the yeast, the finished crust can again be on the light colored side. A third way is to use cold fermentation of the dough with an amount of yeast governed by the desired overall duration of the cold fermentation. If that duration is long enough, the yeast can consume the sugars in the dough and the finished crust can again be of light color. Of the three methods, the last one is likely to be the easiest one to manage in a commercial, high volume setting for consistency of results and for dough inventory/yield management purposes, while also yielding sufficient byproducts of fermentation to produce a decently flavored finished crust. The least flavorful crust would be one using the first method, although using large quantities of yeast would itself contribute flavor (but of a "yeasty" nature) to the finished crust. I don't know if that is a characteristic of a Malnati's crust. The first method would also be impractical if Malnati's uses a commissary to prepare dough balls for their restaurants. As a practical matter, the first method would only work for in-store dough production.
As you know, many of our members prefer to use a combination of room temperature and cold fermentation with their deep-dish doughs. It is possible that Malnati's is using a short period of fermentation at room temperature, followed by a much longer period of cold fermentation, but I have not read anything anywhere to support this method. That method would have the advantage of kick starting the fermentation processs and would also allow the period of cold fermentation to be shortened to something that best fits Malnati's dough management schedule. For example, the total fermentation period could be cut to just a single day. The amount of yeast in this case would reflect that dough management schedule. All we know about the yeast quantity is that the yeast is the last item in the Malnati's dough ingredient list, and that there is less of it by weight than the amount of olive oil, which appears in the ingredients list just before the yeast. For the third method I described, and in answer to the original question you posed, I believe that it would be possible to use an amount of yeast that is considerably lower than what most of our members appear to be using. The amount would depend on the desired window of usability of the dough. I can't say from personal experience, but if I were to try an experiment along these lines, I might use IDY in a range of, say, 0.25-0.50%. This would be for a total fermentation period of about one day.
I might add that another benefit of the absence of salt is that the gluten matrix is not as strong as one when salt is present (salt strengthens the gluten matrix), so the ability of the dough to hold gases of fermentation is reduced. As a result, the finished crust will be less breadlike and more tender, which is what we want for an authentic deep-dish crust. This makes me wonder whether Rudy Malnati understood this effect, as well as the others discussed above, when he first came up with the Malnati dough recipe that is at the heart of the Malnati enterprise today.