Just because we get along so well Gleeok, I'll make a point to check in in about a month or so just so I can see your lovely quest. I am really looking forward to it, this will be your first true Zelda quest and I'm happy to help you test. Your quest probably won't be well received by the ZC community but at least you and I can enjoy it and that's very important.
As for the later levels of LoH:IE I reworked a lot of them for version 1.2 (now on the database) feedback from Yloh and a few others. Level 4 with the 10 blue darknut room used to be the highlight but now its the later part of level 7. That thing pushes me to the brink and back every time I play it. I would highly recommend it to you if you ever decide to pick up the quest again.
Anarchy, I remember your name as well as playing a few of your quests. I remember one which had a large desert and I stopped playing for some reason although I remember that it was quite challenging. Probably because I got stuck finding an item or a bombwall or push stone or some other secret. Anyway, if you do make more challenge quests I'd be happy to try them out.
As far as easy mode is concerned, my experience is that if you spend your precious time and effort making a "true" easy mode (as opposed to a cheap nerf by just halving damage or something) then people will just play that and ignore your hard mode.