I suggest you gove to the John Bridge forum, www.johnbridge.com and talk to the the tiling pros.

Thanks, gardenweb. We really appreciate the frank input on our shower trainwreck. To answer the specific questions: 1. There's a custom fabricated copper pan under the mud, which was installed by the plumber. This is in a a basement, and the copper sits directly on the slab with nothing else underneath it. 2. Yes, we may have forgotten to pull a permit. This turns out to be a pretty forgetful town. I'll deal with the plumber who caused this mess, but priority #1 is keeping this project on track. 3. There is no corresponding cement board on the interior of the curb, yet. It's just exposed copper right now. I'm planning to attach durock there, but please let me know if that's a bad idea. 4. The attached picture shows the "corrected" mud job. We spent a good deal of time measuring and fabricating a form which would allow us to achieve a good slope, and I'm pretty confident this will drain (and plan to test before tiling). So I've at least got one vote for ripping it all out and starting fresh from live_wire_oak. Frankly, that scares me a little, and I'd appreciate any further thoughts folks have about the pros and cons of tearing it out vs proceeding with the added mud. Please don't be shy if we need a little tough love here. Here is a link that might be useful: Corrected mud job

You raise and slope the floor to drain with concrete before starting on pan. You can also hire a plumber to convert cast iron to pvc drain.

Thanks Mongo, You've made my night! I was awake until 1:00 this morning, going around in circles in my head planning my tile layout and how to best deal with the drain, so I'm happy this idea is sound. I actually was considering your second suggestion of floating the tiles up a bit to get a better match, but I like your suggestion of feathering out the thinset below the membrane. I have a hard enough time with the thinset squeezing out with mosaics. I don't need to make it even harder on myself. Now that that is figured out, I'm sure I'll find many other things to obsess about in the three weeks until we have time to do this project! Actually, I do have one other question (for now!): the shower will have two full walls and two curbs at right angles. I have two Kerdi curbs (the gray ones that are reinforced inside) and felt fine about those until I saw someone on a forum somewhere worrying about whether those would be able to support their frameless glass walls. We are planning frameless glass walls too, so I started researching that and couldn't find anyone who had actually talked about combining the two. Kerdi says they are strong enough (and I have an email in to the glass dealer to check), but just wondering if anyone has actual experience putting frameless glass walls on the Kerdi curbs? I checked the glass doors/walls we're getting and it looks like most of the support will come from the anchors set into the walls and there aren't any holes that need to be drilled into the curb (the walls rest on silicone shims), so it seems like it should be fine?