Heya Ryan, I was wondering if I can design a map for your server? I have a plugin called "Terrain Control" which, via an image file that I would make, will generate the chunks.
I already made a few cool looking maps with this if you want to check them out. I will run my server for the rest of the day so you can see the dynmap. Just type in "73.54.167.231:8123" without quotes. I can even do a custom nether:
If you want to check out my maps in person, let me know.
Edit: Created a quick Album with some photos I shot
http://s1342.photobucket.com/user/Alex_MacKelly/slideshow/Map Skills
Edit 2: About my map:
It is (when fully loaded) 30k by 30k blocks.
99% of it untouched by me (I don't have much time to play MC, and even less to build on such a large space) so you can see the full extent of the generator.
Has every biome in game.
Custom biome placement (obviously).
Realisticly sized rivers (minimum 2 chunks across).
Semi Realistic Biome Placement.
Ease of transport, cross the map using rivers!
Is available for download if you want it, I would love to see this map get some love and 30k by 30k is more than enough for your server