One of my best friends trail rides in an English saddle (Wintec), and I have known other people who ride in dressage saddles comfortably. There is really no reason why you can't ride in an English saddle on trail, especially if you're already comfortable and have a balanced seat in that style of saddle, and as long as the saddle fits your horse well.
I rode English for most of my life (arena-riding, huntseat, jumping, some dressage) and when I started riding trail I used my close-contact jumping saddle just because that's what I had. Not bad for shorter trips, but it's really not designed for that type of riding.
I ride in a western saddle now (Tucker) though I kind of regret buying a saddle with a horn since it really serves no purpose and gets in the way more than anything. But. . .well. . .it's a Tucker saddle and I love it.
There are several saddle-makers (Tucker included) that do English-style endurance and trail saddles and I would give serious thought to getting one of them.
Thanks for that tip.