Well, I spotted a blurb on this when I was doing laundry at my Mom's (and had G4TV on), and when I looked it up last night I decided I'm going to have to see about upgrading my PC this year... maybe they'll do a Mac version.
Roller Coaster Tycoon 3, now in full 3D.
Screenshots are scaled down to 320x240, full sized ones (640x480) as well as some other information can be found (amongst other places) at Tycoon Planet.
Enjoy.