Although it is more likely that James Evans [ alias Fleming] was indeed 5'7'', and misread as 67'', it is not yet conclusive.
We have medical reports, that this inmate was at times around 160-164 lbs which is rather stocky for a man of that height especially of that period.
If indeed Evans was 5'7'', and he was the Fleming ex of Mary Kelly, he would fit the description short and stocky which figures in many descriptions throughout that autumn.
If indeed he was in-fact 6'7'', then he would not have been jack the Ripper, but his height would have been ideal for plastering ceilings[ sorry about that].
If you have conclusive evidence showing he's 5'7" can you please show it to all to put this to rest? I honestly don't care whether he was 8'11" but he is recorded as 6'7" so until proven otherwise I'd say we have to trust it.