I agree with Panalotta, Peter <us>, odondon, and Ghol. There is nothing at all wrong with using this construction in any person, as long as the verb agrees with its antecedent:
I who have
Thou who hast
You who have
He who has
We who have
etc.
babs and Ghol are also right to think of biblical/liturgical usage. Another example:
Agnus Dei, qui tollis peccata mundi
O Lamb of God, (thou) that takest away the sins of the world
O Lamb of God, you (who) take away the sins of the world
One catch is that in elevated language such as prayer, the pronoun may be elided: Our Father, (thou) who art in heaven. I struggled recently over how to put elisions like this back into German; cf.
related discussion:meet girt about)
>"it is I who is"
>"it is you who is"
In my book these are both simply wrong, even if they're heard in speech.
>It's not I who am crazy
>maybe it's me who's crazy!
The first is correct but awkward because hardly anyone ever says 'It is I' anymore. The second is incorrect but heard in speech. However, the way to say this both colloquially and correctly is
I'm not the one who's crazy!