Inside Dhcp.h, there is a response timeout constant of 60,000. I just changed it to 10,000 (10 seconds), and now timeout occurs about 12-13 seconds after a reset.

int beginWithDHCP(uint8_t *, unsigned long timeout = 10000, unsigned long responseTimeout = 4000);
};

Found here: http://forum.arduino.cc/index.php?topic=105397.0 Hat-tip to jstamour802