So in case anyone else is still looking like I was, I might be able to help you out. I bit the bullet on 3 cases on Amazon made by a company called CellBee. They were each $10.99. One is horizontal, leather with magnet closure. One is vertical, leather with magnet closure. And one is horizontal, fabric with velcro closure.
My iphone 6+, with a New Trent Trentium 6L case on it, fits in all of them. The horizontal leather one is a bit tighter than the others, but still fits and is not really so tight that it would cause any damage or anything like that. There's a little cutout on the bottom of it which makes it easier to get the phone out because you can use your finger to push it out from the bottom. The phone slides easily out of the other two which I prefer.
The strip of velcro on the fabric one is fairly large, so it is kind of noisy when you open it, but I guess that's to be expected when using velcro.
Overall, I'm happy with the cases. I got all 3 because I didn't know which ones would fit and which ones wouldn't. I'm glad they all fit and it's nice being able to switch between them whenever I want a different style. At $10.99 each, you can't really go wrong either. Other similar cases are $40 each.