Update to the cathedral, I've done a little bit of work on the interior decor and placed some enormous windows to let in the light, and I've gotten the shape down for all of the roof save the back. Now I just need to think of something interesting to do with it... My bet is it's going to have something to do with glass. Lots and lots of glass.
My eventual plan is, once I'm done making the cathedral and its surrounding courtyard+walls, to save it as a schematic using WorldEdit and then transferring it into a normal MC save. When it's in there, I'll put it on top of an enormous floating island with water and lava waterfalls flowing off it (through the cathedral) over a massive lake. Try to find a texture pack that truly compliments it, and admire it in all its glory. After which, backup the save file and then uninstall Minecraft. (Not really, but it would be a pretty neat touch.)
If I may give some advice: You need a lot more details. the little things. especially on the cathedral itself it's very boxy and plain. While it's a pretty good structure you need more to make it pop. If you catch my drift. I do a lot of building in MC (well not recently because my group is SOOO FUCKING SLOW) and from what i've seen that's pretty undetailed.
However, don't get the impression I think it's bad! It's very good, it's got all the right ideas. It just needs STUFF to fill in the big empty spaces of... other stuff. That of course it my opinion, you may feel differently!
EDIT: if you ever need help, I HAVE THE URGE TO BUILD SO BAD *sobs*
Yeah, the reason it's so boxy and plain is because I had only just finished building the skeleton of the roof at that point. I intend on doing some interesting stuff with glass to make it pop more.
If you want to build stuff, maybe give a look into Westeroscraft? (Well, you should probably already know about that, but it's a pretty epic project that I want to bring some attention to regardless.)
UPDATE:
I've done a fair amount of work on making the roof more interesting. (The front part at least. the top's still just flat quartz.)
All I really need to do to finish that area off is put something in the flat part at the front. I'm not sure if I'll do a giant crucifix or something else.
The second stained glass window for the side walls is complete. Both of those are mirrored on the other side, by the way. (I love being able to copy and paste so much...)
I'm currently thinking about ditching the Lava/Water motif I have going right now and just going with pure water. It'll take a few corrections (changing the color of the glass in certain parts and so on. Changing the emerald trees to wooden (or wooden trees to emerald) and changing the sandstone to quartz etc. It wouldn't really be too hard, so it's worth considering.
I should probably start taking the pictures during daytime, but oh well.