ok, so my local tack shop supplies a saddle fitter for a small fee. How it works with them is that you tell them what you are looking for, price range and what type of horse you have ( withers, tree, etc.) They then bring out any interesting saddles for you and see which fir your horse. They also sell adjustable saddles, so if you can't find a fit, but have $$ they'll make it fit =) This is all only english though. They also re-flock and fix saddles for you, or fit saddles you already have to your horse. Since the saddle fitter works out of a well-known tack shop, all the inventory is up for grabs. Many people, myself included, sell saddles through the saddle fitter. This way we get our money, as well as the knowledge that the saddle will be put to good use and will fit well on the new horse.
In my experience english and western saddles are a bit different, so unless the specific saddle fitter has worked with both I wouldn't count on them being able to do both. Most tend to focus one way if there are enough people riding that style. In very populated areas you're bound to get more specialized. Maybe a more localized fitter will have experience with both.
Hopefully this helps =)