All the Nexus phones are not supported by Kies. Samsung did this so you can update the phone via OTA. Its a pure Google device as well. Just because it was maybe by Samsung it wont work on Kies. The only way the Nexus will be update will be over the air. The carriers have nothing to do with the program as well.
Sony is different. Sony said them selfs that the Sony phones will be updated via Sony companion.
Currently some people are on 4.0.1 or 4.0.2 on the Galaxy Nexus. Samsung said its Google ans Google said its Samsung. Rogers says its Samsung. No one will know when the update will come out..
Samsung and Verizon in the US updated the Galaxy Nexus to 4.04 way back in May. Samsung in Canada has released no updates for any of the Canadian carriers (except it seems a very few people got 4.02). I think it's clear that Samsung Canada will never update this phone. I updated mine using the instructions at the Google site (link already posted many times on this forum) to Jelly Bean and it works great.
Yes the few people that got the 4.0.2 are the devices that Rogers is selling now. I got all 4 of my Galaxy Nexus with Rogers with 4.0.2 on them. It seems Samsung has not updated the rest yet for some odd reason.
Anyways like i said the Galaxy Nexus is a pure Google device in which will only be updated via OTA.
You could add the Jelly Bean the way you said but most want to stay with the right way just in case anything does happen. All in all tho, Samsung needs to start updating the Galaxy Nexus.