Go to post 9 in the link in post 20 above. This provides the details of my LED installation in the stock overhead lights of my Tradewind. I ordered warm white 36 SMD light panels from Ebay. There are various suppliers you can order from directly from China. The cost is about $3-$4 each including shipping. Here is one link:
Car Interior Light Panel 36 SMD LED+T10+BA9S+Festoon Bulb Adapter DC 12V White | eBay
If this does not work, just plug into Ebay words like car interior light panel 36 SMD and you should find a few suppliers. I have been very happy with the results. The light output is more than the 4 original incandescent bulbs that were in each light fixture and of course the heat output is only about 10%.
I have also ordered some direct plug in Bulbs with 18 SMD on each bulb. I plan to use these on my reading lights and possibly some exterior lights. Here is the link for ordering these:
1156 BA15S SMD 18 5050 LED White Light Brake Bulb Car Stop Turn Tail DC 12V | eBay
The cost of these bulbs is only $1.88 each with free shipping.
Lastly there is a thread about $5 LED lights that is current. It includes info about ordering 16ft of ribbon LED lights and how to install them. I have ordered two strips plus a dimmer for $25. I think there are lots of places to put these light strips in an Airstream. I will post the link when I find it.