I have never seen a cabin inside a Spectre but they do exsist. The pleasure deck version has a cabin underneath and access is through the front side of the cockpit.
Nor-Tech actually has a pretty sweet cabin setup. Blings boat has two seperate cabins. The left cabin entrance goes to a area with a couch and a queen sized berth up on top of the tunnel. The edge of the bed / tunnel is a solid wall more or less seperating the area under the bow. The right side entrance is a small room which can be used as a bathroom with a real toilet and sink area I belive. I know some of them have generators and A/C also, Blings is setup as a bar area. Its pretty sweet.
Nor-Tech Inside.....................
http://www.viewmorephotos.com/pix/va...94/94_0073.jpg
http://www.viewmorephotos.com/pix/va...94/94_0070.jpg
http://www.viewmorephotos.com/pix/va...94/94_0071.jpg