You might want to split the load, being using TeamSpeak for the group audio as you can setup a Server IP at the optimum middle location for all attendees. This will get you the audio component of the meeting.
Then you can perhaps use a standard screen sharing application you can test: WizIQ, TeamViewer or try one of these:
You could stream your screen via an IP but the location of the live stream would need to be located at the optimum middle location to provide the best results.
I got to say, I have been having alot of success with high quality meetings using a combination of Skype and Logmein.com.
All the best,