Hello again...
I was searching all around internet to find some FREE HDRI interior of a expo hall... and I didn't had any success, so I decided to make couple of my own ... and to share them with you. They are made with C4D and Vray but you can use them in any 3D app as a light source or background...
best regards and fast renders...
Bosko L.
http://boskolazovic.blogspot.com/