I just replaced all of our lights with LEDs - Two of them are similar to your pictures. Initially the disk type didn't fit but since the LEDs run much cooler than the original halogens, and they direct all light down instead of 360, I removed the reflector/heatshields from both fixtures. Then just had to slightly shorten the pins on the disks and they fit perfectly.
I bought all of my LEDs on eBay from scintiluna_led. Turned out perfect. I bought from them when I changed out the lights in my cruising boat and after four years all are still going strong.
