I have a meta-project in mind (yes, meta). Ever since I found out a new SimCity was in the works I've been wanting to get my landscape architecting on. I'm thinking of building a settlement that will satisfy this urge - all roads and canals and parks, with empty zones free for anyone to build on.
I would also (yes, here I go again

)like to propose that this settlement, built on Gliese581d or g, would be exempt from import restrictions from
completed CTM maps. This may be a way of letting me build my giant gold obelisk (or what-have-you) without breaking any laws, as well as preventing the rest of the map from being contaminated. This exemption would only apply within the settlement walls, and would allow people to show off builds using rare materials. I myself have several chests of contraband I can't do anything with (please don't tell the authorities

).
Using ghetto-shop I made a plan for the settlement:

The central green area is a park, in the center of which will be a subway entrance to go back to the spawn settlement. Perhaps a teleportation portal can be placed here as well. The park is surrounded by a canal in light blue, which radiates four sub canals that connect it to the outer canal. The roads are grey, with bridges represented by brown.
The dark blue squares represent the urban zones (24 x 24 meters), in which structures may be built to the map ceiling of 256. The red areas are ex-urban (not quite urban, but not sub-urban), at 38 x 38 meters; these zones have a build height limit of 192. The yellow areas are the suburbs, and have a build height limit of 128 and are 64 x 64 meters.
The settlement will be elevated above sea level, maybe 15 or 20 blocks, so that leaves actual building room at about 172, 108, and 44 for the three different zones. The build height restrictions will give the city a more coherent appearance. Each resident will get to choose one of each of these zones (there are 24 of each, which I think is more than enough).
The light green at the four corners are urban forests for your lumber needs. The beige squares will be wheat farms and animal pens for food production. Of course, if you want to build a specialty farm on your zone you are free to do so.
Each pixel is one block, which seems huge for one person to lay out, but remember most of that will be empty space, with the exception of a temporary torch grid to keep mobs at bay. The canals will only be one block deep, so they will be easy to fill as well. I have a ton of cobble from the borehole I dug beneath my tower, but if anyone wants to donate materials I'll set up some chests in the central park. This isn't so much a mega project as it is a space for many different projects to be built together in an aesthetically coherent manner (hence a meta-project).
The outer wall will only be 3 or 4 blocks high and will consist primarily of glass panes (um, can spiders climb glass? I can't remember).
I have some other ideas for it as well, such as skeptically named streets and canals, but I'll save that for later.
If anyone thinks this is a cool idea say so. If you think it is a terrible idea, or that it has promise but should be altered please comment as well. While I think of this as my project, since I'll be inviting others in to build it would be silly not to take suggestions. If there is enough enthusiasm I'll start another thread with this post at the top so that details can be updated as we work things out.