$500? That's a very ambitious project.
Even Hasbro made some kickstarter/preorder campaigns when they recently released such expensive pieces for Star Wars and Transformers and both lines are backed by a lots of collectors who have deep, very deep pockets.
While I love Playmobil, I'm not sure that the collecting crowd is as... motivated. Maybe if you add the Trekkies/Trekkers to the ranks it makes enough people to warrant such a big piece.
A separate bridge set and a separate transporter room might be more my alley as I have no idea how I could display this big ship...