For about the same price, you can buy marine grade interior LED lights ... like on a couple of pages on this forum's sponsor site for example:
http://shop.sailboatowners.com/prod.php?5207
http://shop.sailboatowners.com/prod.php?6240)
One thing to consider is the color of the "white" LED's. The color of many white LED's is a cold looking blueish. (I suspect the one you are looking at probably is a blue hue LED fixture). Other white LED's are described as "warm" which is closer to the yellowish standard incandescent bulbs we all grew up with ... and also that the current crop of screw-in florescent bulbs emulate. The warm color is desirable if you want a more cozy feeling in your cabin -- rather than lighting for a jewelery store display.
Since these are cabin lights, top-of-the-line voltage/current regulation probably isn't critical but still some degree of of regulation is still desirable.
Or check out eBay. Yeah, a lot of the offerings will be shipped from Hong Kong. But you will find a huge assortment of color, fitting type and lumens for 12v applications.
The price of LED lighting -- with much better lumens than before -- has dropped a lot over the last several years.
Anyway, you might want to look around more before getting the LED back-up lights.