Some other suggestions:
1. It is time for the conference to go to a 2-day format next year, and perhaps have fewer parallel sessions. What was a "meeting" has become a true conference -- several hundred attendees, lots of different kinds of talks, etc. (I have to admit -- it's heartwarming to see the community has grown to this scale!) The costs will be a little higher for the rooms, food and A/V stuff, but not double if fewer sessions are parallel.
2. Bring in an invited speaker, perhaps even one per day, from outside the community (only if we go to a 2-day format, because otherwise, it will take away too much time from the community talks). Invited talks can be very interesting, and give great exposure for the community to thought leaders from outside it. I wonder if we can should ask Richard Stallman :-). Not really. Someone senior from a company or open source project that isn't using LLVM yet would be perfect.
3. Charge a small fee for the dinner. It's a great perk but doesn't seem worth diverting company sponsorship money when that can be used for better purposes, like #1 and #2.
4. Give companies space to have booths where they demo their products using LLVM, and anything else. (Industry has become such an important part of this community that we take it for granted, but in fact, it is remarkable that a compiler infrastructure coming out of a research project has been so widely adopted by companies!) There are so many large and small companies involved that it has become hard for them to stand out. Booths will give all of them a way to show what they are doing, and get feedback on it. It works fabulously well for some of the top CS conferences, like Supercomputing (now SC) and SIGGRAPH. If done carefully, they can generate significant revenue instead of becoming a drain. In fact, the SC industry booths have been a major money maker for ACM SIGARCH in the past. Booths also get attendees lots of goodies -- and who would ever say no to free t-shirt or mouse pad?
5. Have a few sessions devoted to research, for students to present the work they doing with LLVM. A 2-day format again makes this easier.
6. Invite a few people from the technical media to the event. I don't know many of the choices but I bet you folks know many more. EE Times, for example, would likely send someone for the invited talks or booths.
Professor, Computer Science
University of Illinois at Urbana-Champaign