I hate to proselytize, but almost all the upcoming books are talked about in TheDarkTower.org (in the Calvin's Corner forum) well before their publication. I am and have been very active on that site.
Calvin's Corner
Also informative for all upcoming King material is the Oracle forum:
The Oracle
FYI, no limiteds of Revival, Mr. Mercedes or Finders Keepers have been published or announced in the US.
Different UK versions, although not limiteds in the strict sense, have been published by a couple of UK bookstores, at least for Mr. Mercedes and Revival. I expect different versions of Finders Keepers will also be done by WH Smith and Waterstones. These are not numbered, but they offer differences from the "regular" UK trade versions. They offer a different color dust jacket or other variation (the Waterstones edition of Revival had blue page edges instead of the normal white. Other than that, it was identical to the regular trade edition.
Revival was done by the UK publisher, Hodder & Stoughton, in a numbered edition of 500 but had a facsimile signature, not a real one.
John