In the research I did on my recent public speaking trip to Thailand, I discovered that a meeting or seminar custom is to seat VIP attendees in the front row. No one of a lesser status either socially or in business would think of sitting closer to the front than their boss, or someone of a higher social ranking. This is a very loose and largely ignored custom in Western meetings, and carries a significantly higher decorum in Thailand and Asia. Since many meetings are rather westernized anyway, don't fret if your speaking engagement is not run this way, but your knowledge and adherence to this custom can earn you some real points with the people that count.
Room Setup
I normally use a semi circular theatre style room setup whenever I can. In my Thailand talk, I found out approximately how many VIPs there would be and set the front row with plush chairs that were obviously nicer and different than the rest of the typical hotel chairs. I befriended one of the attendees who knew what the VIP attendees looked like. When a VIP was identified, either me or my assistant escorted them to a front row seat. I had some time to blow while awaiting the arrival of the Governor so, I went around the room allowing the attendees to name themselves and their affiliations. I started at the back of the room and ended with the most senior official in the front row. These gestures were very well received and paved the way for a very productive speaking engagement.