The wires coming out of the socket go to a junction box next to the hole in the ceiling. Just spoke with the builder's electrical sub and they say there is definitely a transformer behind the junction box. He told me how to get it out and replace it but it's a 13W and he said a new one might be hard to find. He suggested just bypassing the transformer and replacing the can with a newer model with a built in transformer.
How I'm going to do all that through a 6" hole, when I can't really see much in there, is another story.
I was able to by-pass the transformer (cut wires and re-wired inside the junction box) and re-used the existing wiring directly into can, where I replaced the socket shown above with a standard round socket and screw-in 25watt compact fluorescent. Works fine. Cost me $10 for a new can from which I extracted the screw-in socket plate. My local Lowes store had no can fixture with an attached transformer or any replacement transformer like what I removed.