Have you finished Falskaar yet? Well I sure haven't, but if you have you have something even bigger to look forward to(If you haven't heard of it already).
There is a large group of modders working on a mod that will add the rest of tamriel in its entirety to skyrim, complete with doungeons, new items, quests and locations all lore friendly and architectually sound. I found an interview with the one of the modders on gameinformer(link is below) and parts of the mod are planned to release by the first half of 2014.
read more here: http://store.steampowered.com
Edit: link is now fixed, if you still have problems just copy and paste the url into your browser
Edit 2014: For some reason the link decided to commit suicide over the last year so I did some digging and found the original article right here: http://www.gameinformer.com/b/features/archive/2013/07/25/going-beyond-skyrim-modders-build-bethesda-s-entire-world.aspx
Also the mod is called beyond skyrim, and is not dead, here's the trailer for the first section of the mod to be released this summer (hopefully): http://www.youtube.com/watch?v=oCRWN2Emgbw