Custom Terrain improvements?

[Dark Schwa]

I sure would like to do this. Maybe make a whole bunch of buildings similar to the outlet mall, but that have different functions.
Mostly, I'd like to make tile improvements that are huge impressive structures like statues or temples. They cost thousands of PW's to build, but generate 50 commerce or more (from tourism).

What would really be neat is if you could somehow make all the city improvements into pretty tile improvements and lay them inside your city radius.