It must be true - I found a picture of it on the internet:

and a nice poem about it:
$this->bbcode_second_pass_quote('', 'W')ith the Debt Ceiling coming up soon, it
Is time (although some may impugn it)
For coining a halt
To a US default
With a really big monet'ry unit.
A one-trillion coin, it is said,
Could be minted and shipped to the Fed,
In order to pay
What the US of A
Might be forced to renege on instead.
This sizeable denomination
Would be kept out of mass circulation,
The better to sidestep
That such an untried step
Precipitates hyperinflation.
When Republicans finally come round
From running bond issuance aground,
It's back to the Mint
For the Coin, where its stint
Will be wound up with melting it down.
So let's mint The Coin out of platinum!
Though objections there be, we may flatten 'em.
There are ways besides cash
'Round the Debt Ceiling clash,
But there's nothing as clever as that in 'em.