NodeList And Objects ToArray() - Convert NodeList And Object Properties To An Array

I've been working on a function to convert nodeList and object properties to an array. The first question is with regards IE and checking whether the object provided is an HTML collection. The best I have come up with so far, is to test if it's an object, has an 'item' which is a function and has length. The second question is with regards slice.call and a while loop copy. I guess I need to do some profile/timing tests, but I'm wondering if the function merits a slice.call? or should I simplify?

Code JavaScript:
// Some weirdness in IE regarding nodesList and typeof 'item' returning 'Object'
// even though when alerted it returns 'function (){...}'.
// Therefore having to use regExp.test() to check whether it's a function instead.
// Note: _isNodeList isn't full proof. An object with the properties
[Code]..