Butcher block is easy to find in L.A., unless you have an off size like 5' x 3' for a kitchen island.  After much research we found a wood master that made us this block for a reasonable price.  It is a walnut, 4" staggered block.  We found a wonderfully easy method to seal it with food grade mineral oil and Howard's Wood Conditioner.  Super easy to rub on and our client was extremely happy with the results.