Looking awesome, Steve! I stole Donnie's ideas too for Ivy's cage, all the way down to the heat tape under the linoleum, and it's worked out well for me so far!
However, I don't like sliding doors, I prefer swing out doors - either swing out to the side or swing down. So I did that to make up for no tracks! I have two acylic doors that swing outwards, with swivel hinges on each side (top, bottom, side) as locks. The only downside to this is you have to take the extra effort to make a frame, or a few inch lip all around the front for it.
Just an idea to get the gears moving! Good job so far! Can't wait to see the finished product!