I've had this project sitting at around the 50% mark for a year or so.
Its hard to make the effort (and it is a lot of effort) to work on something that you wont see a return on for possibly many years. There is a good reason for this being the case I know.
It will get done one day that is for certain.

p.s. I really need to update my picture and description. Its really old.

you can read about the process on thier website.
Once a project's art is complete it goes up for preorder in the case of a playfield. Which dictates to an extent its time frame.
The rest go into a queue of sorts.