If there was, it would be kind of silly to have for us I think.
Try this instead:
Go to the forum that you want to see the build threads for (Fox Talk, for instance).
Click on the first Build Thread or Progress thread or any other thread tag you find and see what happens.
Don't feel bad. I know it's there and even I forget about it until there's a reason for it to be mentioned. I bet some of the old-timers don't know about it either.
Xenforo has all kinds of little surprises. Many times, you can use things in conjunction for even better results.
Have you played with the skin selector yet? Bottom left corner of your screen (scroll all the way down). Black Moon is my skin. It's a dark theme and includes many other subtle differences.
Aside from color, see if you can pick them out. hehe