Josh you are right, those kennels have produced working dogs but so is Dal Cielo in that most of them do not claim to produce working dogs (in this case we will talk bite sport as work) because that is not their focus when it comes to their program. They are lucky and get a prospect and have someone that wants to work which ends up working for both of them. What should be made note of in some if not most of these cases is that they working lines can often trace back to a Rivale dog as a grandparent.
Firehorse in PA (has produced I think 2 that do work or have the potential to - traces back to Mojo)
LaOnda (I know the dogs but don't know what he has produced - has Rivale lines, but not sure if those are the ones titled)
Steeltown (not sure where located but they are working on producing working lines, not familiar with this kennels lines for work)
Liberty (produced at least one that works but think there are 2 or 3, traces back to Rivale)
Bodyguard (produced a couple that work, one being the first Sch 3, do not know the lines in his working dogs)
Italica Terrae (produced a couple that worked, trace back to rivale)
Rivale Cane Corso (has a couple with titles, trace back to rivale)
Amore Cane Corso (has some with titles, trace back to rivale lines [used to be a partner])
El Mesquital Cane Corso (has the most titled corso in all venues, think there is some rivale but also some American and import that are working )
Tai Nero (PSA titled dogs, breeds off Rivale line as a partner)
There are a couple working groups that you can find on FB that can provide the insight you are looking for into working corsos (I have the most basic of knowledge) that if you are truly interested are probably the best bet to join. Be aware they are a rough crew and have no time for BS