Big Big Train was my second thought after Echolyn, but I was trying to think outside the Yes, Genesis, Gentle Giant, ELP, Dream Theater, etc. box.
Mike Keneally is one of my favorite musicians of all time. I don't classify him or his music, because it's everywhere and amazing. As broad a brush as "progressive" can paint, I find it too confining for Mike. That said, he's done a significant amount of prog-like stuff and it's stellar. Frank's the same, but rarely classified in the prog world from what I've seen over the years. Tull were always borderline for me, awesome at times, but not as progressive enough to be thought of as such...like Floyd, but completely different.