Surprising no one, Bornakk confirmed recently that there's a new set of Kirin Tor rings on the way for those with lots of disposable income in Patch 3.3. With an item level of 251, they're a significant upgrade to the 226 ring you upgraded back when Ulduar came out. You should expect the upgrade process to cost about as much as the last one -- that is, 1000 gold pre-faction discount.
Good to see that they're seeing this ring thing through to the end of the expansion. The initial investment is a bit steep, but hey, free Dalaran portal, and the upgrade price is pretty reasonable as you go.
Patch 3.3 is the last major patch of Wrath of the Lich King. With the new Icecrown Citadel 5-man dungeons and 10/25-man raid arriving soon, patch 3.3 will deal the final blow to Arthas. WoW.com's Guide to Patch 3.3 will keep you updated with all the latest patch news.