why would one need more than one original signed by the trustee of a living trust?

Hello and thank you for your question.  

You don't need more than one original - - it's purely a matter of
convenience.  This way you can hold an original in your personal
files, and your attorney can hold an original in the vault.  The
trustee may want one too.

Multiple signed original instruments are known as "counterparts."
http://legal-dictionary.thefreedictionary.com/Counterpart

Also, although one of the benefits of a living trust is that it need
not be accounted for as part of the probate process, you still may
find yourself providing the trust to the court, to banks, to insurance
companies and the like.  Many of these would be content with a
photocopy, if they were satisfied as to its authenticity.

If you only have one original, take extra good care of it.  At a later
date, you can always create certified copies.  That means that the
person in possession of the original makes a photocopy, stands before
a Notary, and signs an affidavit that the copy is a true copy of the
original.

So again, you can always get by with one original, but why not sign a few?

Search terms used:
counterpart law

Thanks again for bringing us your question.  Although we cannot
provide legal advice to you, I am satisfied that my answer is correct.

Sincerely,
Google Answers Researcher
Richard-ga

thank you very much.

A *copy* of a document is for all intents and purposes...useless. When
a roll-on type white out device is used, with care, and cutting and
pasting with a pair of scissors, then copying the document... It is
impossible to tell what has been done with a copied document.

good point. thank you.