I've recently made a switch from Hudson to Teamcity. Surprisingly, one of my most missed features is the progressive log (console output) viewing. They had an ajaxy interface which allowed the build log to be displayed to the user real time. Instead of continually downloading the log file and scrolling to the end to see what was going on, I could just view it as a webpage.
Has anyone tried making a customization or is this even possible with TeamCity?