Generally these are all "custom" jobs. As far as I know there's no standard arch - too many differences between hardware locations even on similar boats.
Look for a reputable SS fabricator in your area, try to get a look at some of the jobs they've done, and don't be afraid to ask about one you like - owners are usually happy to talk about these kinds of projects, esp the successful ones. If you're lucky they'll also tell you about things that maybe didnt' work so well after all.
1984 Fast/Nicholson 345 "FastForward"
".. there is much you could do at sea with common sense.. and very little you could do without it.."
Capt G E Ericson (from "The Cruel Sea" by Nicholas Monsarrat)