We have an Ifor Williams trailer, which is great but at the moment we are having to put the saddles on the floor at the front, which is far from ideal! The vehicle towing the trailer is full of kids + dogs, so no room there.
You can get a tack pack that fits on the jockey door although they are huge. They sometimes come up on eBay. You can also get a box made on the front where the jockey wheel is, not sure if they are available ready made for the ifor.
Do not fit folding saddle racks in the front of the trailer as one clever friend did. A you have to get everything out before you can unload B nothing is fixed down so can fly about and C you have random bits of metal for horses to get impaled on/wrapped around in the event of an accident/sudden stop/suicidal leap over the breast bar! (She thought it was a great idea and, tbf, never had an accident to my knowledge but it left me cold!)
I know where you're coming from, we have a plastic saddle stand that goes in the boot, we put a cover on the saddle and one of the kids is monitor to stop the dogs climbing over the saddle. those I know who have the tack packs say they are not ideal, they get in the way for front unloading and are not secure.