Brokers for preferreds "direct access"
Mike - When you say, direct access, I think you mean immediate fills.
Fidelity, Scottrade and OptionsHouse, TradeKing
Quotes Yes Yes Yes No
Bid/ask vol Yes Yes No No
Fills Immed Immed Immed Desk
TradeKing was not real good, as they had to call the market maker and they gave a quote over the phone (I knew it, because I had accounts at all these places.
It would take 5 minutes to get the fill, and that was too long. I was looking for "bargains" in arbitrage-type trades, buying one and selling another, so I went crazy waiting for the fills.
Short answer is yes, they give 'direct" and immediate fills.
Market Data 
Markets 
