Lou Malnati worked for Ike Sewell, who invented Chicago deep dish pizza. Both recipes are identical (as far as I can tell), and are based on vegetable shortening, not olive oil. Coniie's in Chicago, which IMHO is far better than the above two, does have an olive oil-based crust.
Malnati's and Uno's do not use 6-in1's--they break up canned whole tomatoes over the toppings and cheese. And they don't use cornmeal (at least none is detectable)--instead they use a food coloring called "egg shade" to give a more golden color.
Chicago Metallic makes great deep dish pizza pans.
I can't believe the deep dish cooking times posted here (20 minutes, e.g.)--I cook mine at 450 for at least 45 minutes, and it comes out exactly like the restaurant.