I am basing this tileset on the work done by SirHoder, as included in the default CDDA install.
It is heavily inspired by “Jolly Bastion” - A Dwarf Fortress tileset that employs colour to give things a less dreary look.
The basic idea is to make the world feel vibrant and employing colour to differentiate between all the various things in the world.
It will be 16x16 which means detail is quite a feat to achieve, But due to gameplay I feel like you need that view distance more than you need to look at my pixels very closely…
Updated 15.11.2013:

[b]Version 0.5: http://ge.tt/9319tpz/v/0?c -Made and tested with 0.9 Stable, Should work for experimental.
Includes both a JSON file for the tilemap and the tilemap itself, aswell as a .txt file that makes this selectable from the options menu.
Happy Cataclysm!