I'm not familiar with Messiaen's Tristan Trilogy, it sounds very interesting. I will try to get a copy of it. I just love to discover works I haven't heard before that give me the kind of uplifting experience you described.
In fact, I'm hardly familiar with Messiaen at all, so I'll make that a project. I think the problem is I don't speak or understand French, so I tend to go more for German and Italian, which I do understand. However, I'm not averse to getting out translations and following along!