Simply put, you need to hire an NA, preferably one that can oversee your project, which would include plans, project development, oversight of the build, controlling vendors and subcontractors, etc. A 75' - 100' yacht, particularly as a commercial venture isn't inexpensive, nor something that will be completed in 6 months. Since you're a millionaire, you should already know about hiring the appropriate staff for projects like this. There are several qualified NA's in your state as well as yards that can handle your project, where they also have qualified designers, engineers and NA's to get your project completed. I've supervised several projects like this over the years and it's not an uncommon request for any design office, as most are in your situation - not being well versed enough to get what they want implemented.
You can retrofit an existing yacht or have a custom, depending on budget and requirements, but you'll need professional help, to get certification and insure you project gets through all the hoops it'll need to hop through. Custom yacht plan pricing will start in the 20k range and will rise quickly from there, depending on requirements and certifications.
I know of a few larger yachts available in Hawaii and a 94' PowerCat is available for not a lot of money, though it does need a considerable amount of work. Ala Wai in Honolulu is where you'll find it. This could be a good basis for a retrofit or remodel, though you'll still need professional help, it's in the water and was once complyed for river cruises.
