Im working on a new home project. this is going to be my greenest build yet. Before we installed led but we did so by installing standard recessed can and then just put the LED bulbs in that. This made for a some what expensive install. Now that LED have matured more its possible to install them directly in the ceiling i believe. However I'm not sure (and neither is my electrician) as to how to do this to code. here is a photo of the light we want to use.

any idea how this might be done while still maintaining code?

its a 9W 620Lumens recessed light

Is it line voltage or does it require a 12V source? :-)

line - 120VAC

It looks like you can just pop it in through a hole in the ceiling, but how would you handle the connection? I think these are supposed to be used in existing cans as a retrofit. For new, it looks as if you have to install cans for them to go in.

I have a bunch of 12V LED lights that look substantially similar to this. I am installing them in my lower level, underneath InsulDeck. We ran low voltage cable through the chases in the InsulDeck form and just punched it through the EPS foam where we wanted the light. The drywall is going up over it. The hangers just poke a hole in the sheetrock and put it up that way. After finish, I will come along, cut a circular hole around it and push the cable up into the hole followed by the fixture. There is a transformer on a switched leg that controls all the lights. Of course, the transformer has to be next to a box which, in turn, has to be accessible. 120V connections have to be in a box and the box has to be accessible. This is my non-Sparky understanding of the basic options you have.

They make a specific light for cans. I'm pretty sure the code can't do anything about low voltage wiring. I wonder if I just install the a box directly above each light and put the Power supply in there. Some other people are saying that because this isn't UL rated I can't install it? any way around this?

This keeps it protected as well keeps the box accessible.

Here's the can retro model

Yes, that is marketed as a retro model. I've seen the install sheets and they are very straight forward. What is the marketing and/or "instruction sheet" for the first model you showed there? There is a bewildering array of LED units flooding onto the market. Even as recently as within the last year I've talked to reps and counter salespeople who couldn't piece out what was what with the products they were selling. I think that is improving as time goes on.

I think your plan to have a termination box at each light might be acceptable in a lot of places. The one question that comes up is access to the box, however.......