My dimensions are similar to what you are considering (25 x 15 rectangle with a 12 foot island), although the layout likely is different because I have a dining area right outside of the kitchen, so I'm not looking for a large table in the kitchen itself. But, if you want to see our initial plans, the layout is here http://ths.gardenweb.com/forums/load/kitchbath/msg0213170520238.html?8
It is a work in progress.

It seems like a galley kitchen without one wall...the island is taking the place of the second side of the galley. It's a nice plan and it makes it easy to access everything....while providing a pathway behind the island, so people aren't walking through your work area.

I think it's much easier to work with, than an island kitchen, with appliances on the back wall. The island can become a barrier to the other spaces...this way, it's a buffer and primary prep area. Hope you find a house plan! An architect may be able to help....but either way, save lots of pictures. It's the best way to show someone what you really want :)