MeetingPlace 7 does support this natively. MeetingPlace 8 by default is integrated with WebEx which does require an Internet connection. There were plans prior to FCS to support integration between MeetingPlace 8 and Adobe Connect/Breeze as an on-premise substitute for WebEx; however, I'm not clear if this actually made it into the final product.
I suggest working with your Cisco AM on this to a) communicate your business need for on-premise-only conferencing. The BU was asking for feedback when making this product direction change; and, b) to understand the details of the Adobe integration.