The sportier the bike, the smaller the frame size IMO. I am 5-10/11 with a 33 inch cycling inseam (85cm) and I was sized long ago at a clinic that had expert cycle coaches etc and they wanted me on a 56 to 57 frame, center to top. I prefer the 56 frames but on a long distance bike where ride is a concern I like the 57 size. Seat post extension depends somewhat on the frame size, my wife on her little roadie does not have nearly as much extension on her seat as I do yet her bike is a great fit for her, it is just a little bitty thing.
This link has the same formulas I have always seen for the last twenty or so years.
http://www.coloradocyclist.com/bikefit/
People who are short torsos or long arms or short legs, other variables obviously compromises have to be made somewhere. With all that, I want one of those Kilo TT and I simply cannot decide between a 53 and a 55, lol.
This quote is important:
"saddle height will be within a centimeter of .883 x inseam length"
This puts me at a saddle height of 75cm from center of crank to top of saddle measured along the seat tube. It should be the same regardless of the bike, mountain bike, touring bike, whatever, it should be close.