Okay-- If you're going to use a PVC or CPE liner, then the Kerdi is unnecessary. The only thing you would need is a vapor barrier behind the cement board, which would consist of either 6 mil polyethlene, or 15 pound tar paper, the bottom of which would get tucked into the top of the pan liner. One other thing-- before that liner goes in (and this is a step even alot of pros miss) you MUST form a mortar slope for UNDER the pan membrane. The reason is that water that gets through the tile, grout, and mortar will get to the liner and if it's not sloped, it'll just sit in the pan, and "ferment". It has the potential to get extremely unhealthy. As long as the liner is sloped, though, water will follow gravity to the weepholes at the base of the drain and exit the shower pan, drastically increasing the life of your shower. As for the niches, frame them, and then cement board them as you will the rest of the shower. Once that's done, you can use one of the roll-on or trowel-on membranes available, such as Custom Building Product's Redgard, or Laticrete's fabric reinforced 9235, or Hydroment's Ultraset. You coat the entire niche, as well as 6" out onto the wall in all directions from the niche. Piece of cake!! :-)

I think it would be fun! And I doubt your bottles of things will cover up EVERYTHING! You'll get a peek at the contrasting grout! It's not like you're putting super expensive metal tiles or something in there :)

I got a 20x40 white fluffy microfiber towel from the Rag Co. and have been using it for about a week. It has its plusses and I don't regret buying it, but I'm a bit on the fence with it. First of all, I didn't really hate using my squeegee. For flat, unbroken surfaces, a squeegee excels in moving water quickly and easily. It sits relatively inconspicuously in my tub/shower. It's not so good at the fixture end of the shower and you can't use it to wipe chrome. I think one problem I'm having with the 20x40 towel is its size. It's unwieldy. I wonder if I can just cut it in half. I think that's all I would need even if I used it on its own. I've been hanging it over the tub to dry, but I'm not wild about how it looks. This may sound crazy but I think using the squeegee to chase the drops off the tub surround walls and along the tub ledge, followed by a polish with the fluffy towel, would be the best for me. It takes less than 1 minute (you can do a lot in 60 seconds, which is how long I swish my mouthwash).

cgcl- Whatever heat is supplied by a heated shower floor is trivial compared to the heat of the water. A shower runs at about 105 degrees F, skin temperature is about 98 F, and you would never try to heat a floor to those temps. Even if you have a heated floor, it will still be cooler in comparison to your skin. On the other hand, as soon as water at shower temperature hits the floor, the floor will be heated in a few seconds far more efficiently than resistance wires in the floor can provide heat. The fact that your shower is large doesn't affect things because I can't imagine taking a shower while standing somewhere that the shower water isn't hitting. It's your money and your project, so do what you want. But, to me, a heated shower floor is an unnecessary and expensive complication that won't make any difference. Further, because the mass of the shower floor is large, there would be so much thermal lag that you would need to have it on all the time: you couldn't just turn it on when it's time to shower and expect it to quickly get warm. I can think of a lot more things to spend money on in a bathroom that would actually add value....