In our boat the interior lights are all powered by halogen bulbs. Over the past few years I have been replacing them with LED bulbs. The small cabin spot lights have G4 bulbs and I have not until now been able to source a LED replacement that will fit. I have found a supplier and they are great BUT a small modification needs to be made to get them to fit. The reflector section can be removed by slightly rotating it and it will pull off. This leaves you with the frame, the reflector and the glass. If you twist the reflector it will come out and then the glass can be removed and discarded. The hole in the reflector will need to be slightly enlarged. I just used a pair of tapered pliers and twisted them so that the hole was stretched a bit to fit the bulb through the hole!
What a great result and for a fraction of the cost of new lights. You can get the LED bulbs from eBay. Just click the link below: