Ah, meant to say, often looking at custom. That one is pretty sizable, and I think there are some other large frame bags no longer made, but the larger they are, the fewer frames they'll fit well.
If you think it'll fit your bike, i'd say go for it. It looks like it would fit on a good range of bikes with top tubes close to level, not sure about it on a bike with lots of slope, like medium and smaller modern MTB frames.