I don't know if anyone has posted this idea - apologies if they have - there are loads of threads and emails floating around !!
From reading the transcripts of the interview on the Eddie Trunk show it appears that Mike hasn't fallen out with the guys, still wants to be in the band and would like to return in the future (which JP has also welcomed) - at the moment, MP is just stale and feels burnt out. So, instead of replacing him permanently, how about getting in a session drummer to do the album and tour next year ?
That way, the "temporary"drummer won't have to feel that he is replacing Mike and won't be scrutinised so heavily by the fans, with every aspect of his performance under the microscope. He will be in to do a job in 2011 and perhaps part of 2012 before departing with the band (and fans) thanks.
DT usually release an album every 2 years. After next years album, the follow up probably won't be until 2013 - over two years away, which fits in with Mike's required hiatus. He can then rejoin the band and everything will be rosy again !
I am sure there have been examples of a band member being too ill to tour and being replaced, temporarily, by another musician, but still remaining in the band. I remember seeing Toto in 1995 when Greg or Matt Bissonette (can't remember which !) replaced Simon Phillips on their European tour because Simon was ill; however, he was back the next tour. Although Mike isn't ill, he is "not available" at the moment. So why not replace him temporarily, on the basis that his replacement will only perform in a session capacity ?
There must be drummers out there that could fill Mike's shoes for one album and the tour to promote it, but where the "long term" chemistry isn't so important. This way, DT could tailor their live set to exclude really technically demanding numbers that might be beyond the capablities of the session drummer (eg "The Dance of Eternity"). Whilst the session drummer will obviously have to be technically competent to be in a band like DT, they will not necessarily need to be capable of playing the entire back catalogue, as they will only be in for one tour.
Given the departure of Mike is slightly unusual (when most musicians quit a band, it is usually for musical differences or because they can't get on with the rest of the band) I believe a temporary replacement could work.
Peter