For those high FPS claims, they all appear to be taken when they don't have any activity on screen: when thats the case, FPS always jumps very high.
For a better test of FPS, go into creative, build a 25*25*2 block corral, place and then make sure you are looking at 45 or so visable entities (villagers for example), and then check. That way MineCraft has to actually be doing something on screen and that puts a more realistic idea of what the FPS is capable of.
Note the latest claimant doesn't say what sort of hardware he is running: for certian it isn't any mini out there (None of the GPU options have that kind of horsepower), and doubtfull (But not impossible) that it is an iMac either. By the looks of it, I'd say a Mac Pro, or a windows machine mainly for GPU reasons.