Haven't seen the ones you mean, but worked in that industry for many years. I can tell you that one of main manufacturers of beige sockets in caravans is Clipsall - so it may well be them. They're available through many wholesalers nationwide. If you had a picture I may well be able to find out for you.
These are nice but not what I was after, I just can't find any photos of the ones I want. They are very slim, they seem to have bezels that are available in loads of finishes and the internals are modular.
If you mean really slim and not like the Volex example above - have a look at MK Aspect - http://www.mkelectric.co.uk/products/ranges/rangelist.asp?RangeID=1060
Clipsall that I mentioned above are modular and available in many finishes. Most companies now make a flatplate in many finishes - Look at GET
There are many European suppliers with modular ranges. I'm not so familiar with these - have a look at Ave (acute accent on the e) and Legrand. There are many others - just can't recall them right now.
If you want to search them out I suggest trawling through the manufacturers websites as there are many ranges available that you won't easily find in the major distributors. Alternatively, why not ask the boat builders?
If you mean the really small ones that are a direct replacement for the small continental type sockets made by Berker I got some from
Plug In Systems aka Caravan Electrical
Grange Park Lane, Willerby, East Yorkshire, HU10 6EQ
Tel: 01482 659309
Their web site is no good best to call them and describe what you are after. the sockets come as a set of parts, ie face plate , socket and and back box, you will need all three components as the back box is slightly deeper than the continental ones.
Found some at eas coast leisure sockets and Flap
as well
hope this helps
Take a trip to the local Caravan / Camping Superstore. Most items are the same with different label and at different pricing to Marine.
With regard to sockets / switches etc. caravans have similar requirements to boats ... size, compactness, and also resistant to vagaries of cabin atmosphere !
While there check out other items .... hatch stays ... electric hook-ups ... etc. Galley gear ... solar showers ... list goes on !