[Ahban]

"There are none so blind as them who will not see".

[VadeRetro]

"There are none so blind as them who will not see".

Grammar is irrelevant but I think you have to choose between "those who" and "them as." (He said snidely.) ;)

[donh]

"There are none so blind as them who will not see".

There are none so useless as those who will see anything at the drop of the slightest vague hint.