To research for preferred class shares, read through the company SEC's filings.
I can verify PLD: it has 3 preferred classes: Class G, Class F, and Class C. The following excerpt from PRNewswire on 03-Mar-2008,
"ProLogis PLD, the world's largest owner, manager and developer of distribution facilities, announced today that its Board declared a dividend in the amount of $1.0675 per Cumulative Redeemable Series C preferred share, payable on March 31, 2008, to shareholders of record on March 17, 2008. Series C preferred share dividends are cumulative and payable quarterly at an annualized rate of $4.27 per share.
ProLogis' Board also declared a dividend of $0.4219 per Cumulative Redeemable Series F preferred share, payable on March 31, 2008, to shareholders of record on March 17, 2008. Series F preferred share dividends are cumulative and payable quarterly at an annualized rate of $1.6875 per share.
In addition, ProLogis' Board declared a dividend of $0.4219 per Cumulative Redeemable Series G preferred share, payable on March 31, 2008, to shareholders of record on March 17, 2008. Series G preferred share dividends are cumulative and payable quarterly at an annualized rate of $1.6875 per share. "
According to the best of my knowledge, only Series G is traded.
Plan9