Ok I'll spill the secret.....
There are a couple of ways to get a good finish on the interior of refer boxes etc. I'll start with my favorite first.
In Alaska I did some comercial boating for a bit, and a bit of repairing and assisting with some of the fish boats up there. I noticed that a lot of them had really strange patters on the inside of their fish holds, which are actualy big reefers or freezers depending on the boat. Upon closer look once I noticed that the patters were little tiny teddy bears.... Really...... Another boat had mushrooms. It became immidately apparent that they were lined with Paper towels saturated in epoxy. The result is very strong, easy as heck to fabricte, and repair is beyond easy... Now the fish guys used whatever was on sale, freqently droped huige heavy pokey fish on it and all was good.
Fabrication is easy, take a small piece of the foam insulation that you want to use, mix up a small atch of epoxy, and smear it all over the little test piece of foam....Did it disolve, (Most don't but always good to check). Then if not, cut the foam, glue it together for the shape of the box, lid what have you. Then wet out the paper towels with epoxy, and place them over the foam. Do it nice and neat.
Oh and if you don't like bears or mushrooms, you can use the blue shop towels or the plain white ones at the grocery store. Our last boat I did this for the whole box, and it lasted longer than we had the boat, only one repair, which involved the box lid being dropped on the cockpit sole from about 6 feet, had to fix the corner. Took about 5 minutes fo rthe fix, counting cutting the foam....
If you want you can of course paint over the paper towles, but why go for the extra work, just get a pattern you like!
Monel or stainlesss lined, find someone that does comercial kitchens give them a pattern, a month or more of your salery, and it looks awesome. Make sure that you have enough insulation, and that you have completely removed the counter in the galley to install the fabrication, should only take you a couple of weeks worth of full time work to go this route.
Vacuum panels, give someone three months of your salery, and make sure that you can get it apart the 5-10 times that you are going to have to take it back when the vacuum leaks out...(Or is it in....?).
You can fab the whole interior our of fiberglass, but it seems to me to be a big waste of time and money. The paper towles work awesome......
You can also have someone make up a molded plastic interior, or you can cut and weld the interior yourself. I have seen both, the issue is that the plastic can get kind of funky with odors etc.
Guy