There are a few smaller bike manufacturers that have commuter-oriented road bikes. I just happened to look up one and saw this:
http://www.torkerusa.com/bikes/commute/2012-u-3-

This is a drop-bar 3 speed bike. Its not the "fastest" road bike (i.e. it does not have the bells and whistles that make it look fast), but its relatively cheap ($500 new), and the lack of external derailleurs might be a plus for negotiating it up narrow stairs. Its not quite as nice as some of the bikes at the $500 range on BD, but unless you know how to repack hubs and tension wheels, the support of actually buying it from a local shop might be worth it.