There is less then half the makes as there are names! There are very few companies that represent themselves and build all the model tractors they sell! I like the brands that do build their tractors vs out sourcing them as it is always easier to get the parts ten to twenty years later!
I'm not fond of the component tractors at all as they age and need repairs as parts are often a problem with age.
What makes are you referring to that do not outsource? ALL of the major brands in the USA outsource. Most, if not all, of the major brands in Europe outsource. The largest companies I can think of, (and I am familiar with most all of them!), that do NOT outsource to other tractor manufacturers are MTZ/Belarus. however, they have licensed their tractors to several other somewhat related companies.
Fendt and Challenger do not sell outsourced tractors, at least technically or currently. Both are part of AGCO and sell tractors from various parts of the operations. Challenger USED to sell rebadged Iseki and Carraro/Agritalia, but no longer do.
John Deere, Case IH, New Holland, Massey Ferguson, Claas, Landini, McCormick ALL sell outsourced/rebadged tractors.
Going down to smaller manufacturers, Kubota, Daedong/Kioti, LS, TAFE, TYM are not selling rebadged/outsourced tractors, although some market other makes as well. (Daedong-John Deere, LS-New Holland, TYM-Case IH and TYM-SAME).
Just a thought to ponder!