I have done some research on the Summerset Isles but haven't come up with much. I'm writing a fic/character story thing that I will soon post here but I don't want to give too much away so I'll try to be vague about those details.
There doesn't seem to be a clear answer about anything to do with the Summerset Isles, the information we have seems to be about guesswork and assumptions. I'm trying to work out the weather, the terrain, the background of the island. There aren't many official statements out there that I can find, so I want to know...
What do you think the Summerset Isles are like?
From my own findings, and my own imagination, I think it's a place where the Altmer have strived for perfection. Perfect, sunny weather(controlled by magicka, and constantly maintained), mostly flatlands (but of course there are mountains and such) with large cities, buildings almost like skyscrapers. Very elegant and organised and filled with wealth. It's very closed off, as we all know, but I think it's closed off from the inside as well. No one can get out without express permission, and of course, no one but High Elves can get in.
I could be perfectly wrong and there could be a whole book about the Summerset Isles that I've completely missed. If so, please point me towards it, I need as much info as I can get ^.^
I too am creating an Altmer character this was helpful to me...
http://www.uesp.net/wiki/Lore:Summerset_Isle
If you scroll all the way down you will find a list of books that can be helpful, also here is a link to a map of the island this might help you as well; Summerset Isles
Hope this helps you.