How would you lock a card in place.. so it doesn't move in anyway, basically acts like a table background image or w/e
This is a very good idea and something that would be very easier to add. You are actually talking about 2 different things, though. Locking a card so it is immune to all changes (except for unlocking it) and making a card always appear on the bottom.
I suppose that I could just simplify things and have a "lock" function which makes things unalterable, and as long as you put it on the bottom first, new cards wouldn't able to be put on top of it. Alternatively, I could just draw these locked cards first and lower in the z plane.
Any thoughts?