Mushroom ID Help Requested

A friend found this mushroom in her backyard among some oak trees.  We are trying to identify it, but still don't have a positive ID.  Here is what we know:

• It is about 14 " in diameter.
• It's form looks almost exactly like a chicken mushroom, however the color is a light dull beige toward the outside and whiter to the stem.
• When touched it bruises to a black color.
• It looks like a Berkeley's Polypore on the top, however there are no large pores on the bottom.  The pores are very small and shallow and the underside appears almost smooth except when viewed with a magnifying glass.

Any help in identification would be appreciated. Photos are below (click on any image to see a larger version of the photo in a separate window).