Most "large scale" projects are scratch built.
Not to hard for a couple of experienced plane junkies I would imagine.

http://www.floatingdrydock.com/

is one of the best resources for ship plans.
Most of our heavy cruisers at 1-72nd scale come out around 8-9 feet long.
Once you have decided on a scale, which ship, and have your plan set.
You just need to start hacking plywood.

If you need direction in the process holler some more.

Aimee