They cost a bit to build mind you, the interior is alpha and omega.
Some examples:
My cousin's bus back in 07, they won concept of the year - but the bar has been raised insanely since then:
Here they're rigging sound equipment In the "main ring" on the Tryvann event:
Get the party started
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On another note I'm sticking to designing "cover name" logos and other stash for this years buses, not being part of one myself - can't afford it.