You can do quite a lot of customization to your UBB.classic board. I doubt the other sites you were looking at had multiple licenses or instances of UBB.classic running. Perhaps if you were to point out the sites and what it is that you want to emulate we could tell you how it's done.
To get you started, you can create different style sets that you'll use for your different forums. Each style set can have different color schemes, headers/footers, custom HTML, etc.. You create/edit these schemes in the Control Panel, under Display Options > Styles.
Once you've got a style set or two to work with, you can assign them to the individual forums. Go to Forums > Forum Settings. Click the "Details" link after the forum whose look you want to change. Towards the bottom of the next screen, you'll see where you can select the style set and template that you want to use for that forum. In this way each forum can have it's own unique look.
Go ahead and experiment. If you have any specific questions, we'll be happy to help.
