I haven't seen a single master thread here on the Disboards, but there are plenty of other websites that track/post refurbishment schedules and rumored refurbishments. Wdwinfo has a list (http://www.wdwinfo.com/disneyland/plan.htm#rehab) and there are also other sites that have lists of closure dates. Just keep in mind, that all information is subject to change without notice. (Right now, the re-opening dates for the Rivers of America attractions and train are mostly guesses/rumors, so those might vary considerably across different sites).
The list that @ImTooExcitedToSleep maintains on the DIS that figment_jii linked to is official information. We won't post closures unless it's been confirmed by Disney.