fwiw, many of the Crosby saddles and the older Collegiate saddles made by Ruiz Diaz were sort of intended for the American market. A Crosby medium tree might work nicely. The Crosby California Prix des Nations, in my opinion, was a wider and straighter (flatter) tree that was kind of aimed at the QH market for a while.
Wintecs, as someone mentioned, and the latest APs and dressage models are for a flatter back than the pre-2009 ones. I don't think they changed the close contact tree at all, so any year of 500 or Pro Jump cc might fit.
If you know that you want to show or jump, then get a close contact. Some of them are minimalist and plain flaps and don't have knee rolls or blocks. But some are at the opposite end of the spectrum and are more like and an AP but have a square cantle.
Keep in mind that Toulouse saddles seem to run narrow. Many American horses are wide or XW in that line. It was sold as Intec or Flex Rider before it became Toulouse.
Some of the HDR saddles are also rather narrow. HDR was sold as the Nice brand, and those are a good value that sells for low prices.
Stubben: Probably don't even look at any tree width less than 31 or 32, unless it's an older Stubben Siegfried or other AP that ran wider.