So, when I started imputing my own version of the Lost City (from pencilled scratches on looseleaf paper to typed and formatted) I've been editing, re-writing and adding new material.
When I got to the lower tiers, I LOVED the ideas of the paintings on the walls depicting some kind of descent into paradise and my imagination just started to run with that - what if it really was a linear "Descent to Death" that pilgrims would embark on as a religious act? What if, in a world where magic is real and containable, the journey was "immersive" - somewhat like a holodeck on Star Trek?
And, of course, there have to be challenges - so I used the paintings that Moldvay detailed as a springboard for a Descent to Death in the Daen Ral campaign version of The Lost City. I used this to replace Tiers 6-10 (well, 6 is VERY similar to Moldvay's - so I guess I really just replaced 7-10 but I digress...).
I also have pages of notes for the Underground City, a fair amount for the upper ruins and some expansions for some other underground areas.
So, all in all, probably a campaign in the making. Here's one thing, though. None of it is scaled. Whereas Moldvay had the upper tiers be Dungeon Levels 1&2 - I have some really powerful undead on those levels (though often tied to their particular location somehow - so "run away!" will still work for lower level characters) and a few unopenable doors (without the proper keys - yes, one of them is in Zargon's lair). One trap, if triggered, takes the PCs to a demi-plane with a trapped beholder and another BBEG (based on a Dungeon Magazine adventure - Object of Desire). Part of Tier 5 is a hidden area and is based on another Dungeon adventure (the Pit). Some of the Upper Ruins come from yet another Dungeon adventure - Telar in Norbia (which is CERTAINLY not scaled for levels 1-3).
So, I'll post some of my stuff. I'll try not to step on too many copyright toes. Oh - and if you LOVE the lower tiers the way Moldvay wrote them, fine. I have no beef with you - I'm just going to post my idea of what I want the party to experience as the lowest levels of the pyramid tomb of Alexander and Zenobia. If you get some ideas from it, maybe it could be an additional level or whatever - or just ignore it. I'm okay with that.