Looking to commission a working Model of yacht

There is a massive amount of scale model boat enthusiasts all around the world. Many many web sites and forums specific to RC model boats too. I'd suggest having a look at a few on-line model forums and see if you can find one that you think is fairly switched on, join up and ask some questions. In my experience they are an enthusiastic bunch
The larger yacht builders all have their own contracted model makers, all under heavy confidentiality agreements. If you want an exact model made of a particular yacht, your first problem is getting hold of enough design information for the model to be made...this wont be possible from a company under the above confidentiality agreements, but there are model makers out there who can make a model that at least closely resembles the yacht in question from photos and basic information available on line.
Your second problem will be how the model is to be made.
A one-off model will be expensive, whether its made from GRP / FRP out of a mould or scratch-built from plywood etc. A lot depends on how complicated the superstructure is etc. Either method can be built from conventional 2-D drawings, or 3-D design information.
I've seen some spectacular RC model yachts built both ways. These days its quite common for model making enthusiasts to utilise CAD/CAM. The initial design is created with 3-D software, and the tooling required to make the moulds are machined direct from this 3-D info.
3-D design information can also be used to make a model in the more traditional way of frames and outer skin...in this case the 3-D design is sectioned up, and printed off to the right scale. The frames etc are then cut by hand etc.
You need to decide what material your model is to be made of, source if possible enough design information to get the model made, and source a model maker who is happy to work with the information and material you prefer....unless the model maker can prepare the design info himself of course. Dont forget that many professional model makers will be concerned with the intrinsic copyright in the original design. If its a one-off, just for you, there shouldn't be too much of an issue but if it was, say, a model that could be marketed, that is an entirely different scenario. Either way, good luck, and if it progresses, post up the pics.

Google is your friend:

http://www.google.com/#hl=en&q=RC+model+yachts+custom&aq=f&aqi=&aql=&oq=&fp=86f43777e436a6c1

There are so many Longranger5, I'm sure a bit of Googling will throw up plenty of choice. Its the same with actual modelmaking companies. Many sources in Asia by the way...very talented modelmakers out there.

A selection of companies I've looked at before...

http://www.yca-hk.com/yacht-model.php
Although they seem to concentrate on display models, they may be willing to quote for an empty shell that can be adapted for RC . I stress that there are literally hundreds of similar companies around the world.
Two things to note looking at that site...they have a pricing guide depending on size of model...they also list their requirements for what they need from you the client to be able to make the model. 3-D design info is a must, and I assume they then machine the tooling from this and make moulds for the major parts of the model.

http://www.model-ships.co.uk/index.php/fuseaction/shop.category/categoryid/31

And finally this one which looks very exciting indeed...
http://www.captainsmodels.com/

If I seem to be banging on about 3-D, machined / milled tooling, and GRP material, then I confess that this method of large model construction would be my personal choice for an RC model.

By the way, have you seen the beautiful 3-D renderings of Amevi on here done by our very own Apache2k ?.....commissioning a similar 3-D model which could then be processed by a company similar to my links above isnt such a crazy idea.