Items remaining til free shipping

So the problem is that people apparently can't read the 200x500px "free shipping on four items or more" at the top right of every page. As a result we have people paying $30 shipping on a $450 coffee maker when they could buy $40 of coffee and get the shipping free. We've even talked to a few, and they "didn't notice" the deal or they would've taken it.

So I've found the "Free Shipping Qualifier" sidebox, and I figure it can be modified to deal with free shipping per number of items instead of a dollar amount. What I can't figure out is the replacement for:

Code:

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MODULE_ORDER_TOTAL_SHIPPING_FREE_SHIPPING_OVER

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I've searched in the dev toolkit and not found a similar call to return an item limit instead of a dollar limit. I'm thinking this modification would be even simpler overall than the dollar amount calculation, using

Code:

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if ($_SESSION['cart']->count_contents() > 0)

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and calculating the difference in number of items. Can anyone point me to the call I need to make?

Thanks in advance.