Earlier today I attempted to embark in an evil biome using a version I found in the modding forum that allowed me to start with 70 dwarves. The catch? I simply hit "Play Now", which gave me the same skills and resources that the regular version gives. It wasn't as challenging as I had expected, however; the only reason the tantrum spiral became a tantrum spiral, instead of one crippled dwarf flipping out harmlessly is because I went out of my way to generate the tantrum spiral (I had never seen one firsthand before). If I hadn't, the fortress not only would have wound up being successful, but would have wound up being successful far faster than any of my seven dwarf forts due to having sixty-three peasants to shape as needed.
The one theme I keep coming back to as one I want to attempt - and that is difficult for me to properly attempt - is an above-ground castle city. Exports would be food and crafts, primarily, with as little actual mining as possible, and tens of thousands of units of stone bought on embark to facilitate this. A dedicated military would be mandatory, which would mean importing weapons and fuel - no mining means no local ore, bituminous coal, lignite, or magma, and trees take a long time to grow, especially at low FPS, limiting the usefulness of burning them to fuel the forges. The problem I keep having is the digging restrictions. It's always faster to excavate a fort than to build it on the surface, which makes digging really, really tempting.