Dear Starchild;
Okay so here's your list of potential co-sponsors.
To take the positive route - who on this list is a real genuine organization or multiple organizations for co-jointly co-sponsoring an event and having people show up because they are politically motivated to do something? Secondly, why would they co-sponsor? You need to have this question answered before you call on them so you can overcome objections. Who is their contact person? What internal resources do they have for contacting their members and doing so on relatively short notice? What is their membership? Obviously the larger the actual dues paying membership or otherwise the better.
How active are their members in political activities of one kind or another? So on and so forth.
In other words what's the curriculum vitae of the group which are most likely to consider ajoint co-sponsor and the most important question WHY should they work with the LPSF in the first place?
This is another question which needs to be answered before you call on the groups leaders.
I am approaching this on a marketing advertising sales basis. What's your target market and how does this event address the target market and why should that group be part of the process and if so does the target market address the organizations reason for being in existence in the first place?
Okie Dokie?
Ron Getty - SF Libertarian
Hostis res Publica
Morte ai Tiranni
SF Pink Pistols
Americans for Safe Access (medical cannabis)
SF Taxpayers Union
Sex Workers Outreach Project
Erotic Service Providers Union
Antiwar.com
Pacific Research Institute
Idriss Stelley Action & Resource Center (police accountability)
Outright Libertarians
Small Property Owners of San Francisco
War Resisters League - West
Affordable Homeownership Alliance (Sarosh's group)
San Francisco Late Night Coalition
Californians For Electoral Reform
SF Ron Paul Meetup Group / Campaign For Liberty
Golden Gate Restaurant Association
9/11 Truth Alliance
Movement For Unconditional Amnesty (migrant rights)
Mexican-American Political Association
Oh, now you're just being mean, Ron. You know marketing language drives
Starchild up a wall. 
Ron Getty wrote: