Sigma has posted sample pictures for the new Sigma 105mm and 150mm f/2.8 EX OS HSM Macro Lenses (select the 150 samples using the left navigation bar).
B&H has the Sigma 105mm f/2.8 EX DG OS Macro Lens (for Canon - accepting Nikon preorders) and the Sigma 150mm f/2.8 EX DG OS Macro Lens (for Canon and Nikon) in stock.