I found some matte black center caps in G.R. at Grand Sales, I think they've got a few sets left.
EDIT- Man I really do like those Liberty caps better every time I look at them....
Very nice consolidation under the canoe rack, should make trip loading much easier! Also gives you a good opportunity to tarp all your fine things if you do any dirty work in the garage like cutting or grinding. I'm inspired, thank you.