I think I found the tomatoes they use. Their own "Lou Malnati's California Vine Ripened Tomatoes" label says Hollister, CA. A little Googling gets us to San Benito Foods, a division of "The Neil Jones Company". http://www.sanbenitofoods.com/nwpack/default.asp?session=8263197646
I ran a quick search here and the brand has been discussed before on these boards but never in relation to Malnati's. Obviously, they do some private labeling of their product.
Would be nice if I could locate a can in Chicago to try them.
I like my "San Marzano" white label diced tomatoes (distributed by a company in New Jersey), drained, with a bit of the crushed SM tomatoes added in.
That gets as close as I've ever gotten to matching the taste of the Malnati's/Uno tomatoes.
They are also grown in California (if we are to believe this website: http://www.san-marzano-tomatoes.com/canned-brands.html