Try and Google 16teak and holly plywood in Florida. Lots of choices.

The laminate product (Lonseal I think) available from Defender in the satin finish is so close to the original you wont be able to tell them apart when on the boat. I posted whole narrative on what I went thru doing this project and, while it can be tricky , I highly recommend the product over the laminate originally in the boat.

A couple of other posters used this too and will probably add some insight.

The Lonseal laminate makes sense to me somewhat.  My teak/holly sole has been ruined, stained and peeled way by water over time:  Rainwater dripping in through the companionway hatch.  Rainwater splashing out of the shower.  Water from my air conditioner bucket when it overflows (long story).  It's been a very disappointing floor design.

Let's say I replace it with Lonseal or some such.  What about the plywood underneath the laminate?  Won't the laminate unpeel when water soaks into the plywood beneath it?  or am I misunderstanding its design?

You can't just lay the vinyl over the old laminate as it will be too high. You need to cut new bottom layers out of 1/4" marine ply, then laminate on top. The ply and the vinyl are the same height as what you have now.
 

Ben,
After you attach the laminate to the plywood, you should seal all the exposed sides and edges of the plywood with epoxy. Without sealing it you will be doing the project all over again in short order.

Actually I sealed the plywood with a couple of coats before I glued the lonseal down. Been a number of years now and no problem with it separating.

Sounds like a lot of work for someone like me who lives on their boat with no garage or shop with all the tools and such. 

I was hoping that perhaps a company already makes the finished and sealed product in various plywood (or better yet artificial wood) thicknesses.

When I first started this process I went to Catalina (not Catalina Direct). They wanted me to send the original piece back to the factory to use as a pattern. You'd think that they would know the size.  In any case, couldn't find anyone else.

You are correct in that you wouldn't be able to do this project as a live-aboard without space to lay everything out and some tools. Maybe there's a woodworking shop near you who could do this for a fee if you supplied the materials., as an alternative.
 

One thing I didn't notice before is that your in Florida. When I was doing this and mentioned they wanted me to ship the original back to the factory, they were still in Calif. Maybe you can just drive to their  current location with the pieces.