Having people submit questions via PM to *maybe* 10 people has a high potential for a disastrous outcome. Once you managed to drill the fact that you need to double click the names of the people in red, then ask your question, then click back, you will have unleashed a never ending torrent of text to those moderators. 6,000 users trying to PM 10 people questions, and repeating them in CAPITALS sixty-four times because it wasn't answered immediately will become very stressful. They just won't want to wait, or be orderly about it. One solution is to maybe have a very simple WordPress plugin under the Ustream applet on the /live/ page that people can enter a question and submit it. It could reject duplicate questions (either altogether or from the same IP), and could restrict submissions from each IP address to a couple questions. Then someone can feed the mods the questions. (It wouldn't even need to be a WP plugin, a "simple script" and some embedding would do the trick). Anyways that would be how the solution for that can be handled. One way anyways.
As for more prominent exposure, I think going to the YouTube "celebrities" is an excellent idea, Jeph. There are many YouTubers who would probably be happy to help. Is SVC doing any online advertising? i.e. adCenter, Yahoo! Ads, etc? I think this came up during a live show a few weeks (or more) back, but what about advertising on your local community access, Ben? Ranting daily would actually be pretty sweet. It could be an excellent lead in for a that weeks series of dailies.
In a general answer to the thread title. SVC should never sacrifice quality over quantity, and in the limited time that I've had the privilege of being a SpaceVidCast member, I can say that I don't believe this will become a problem. Other than that.. I'll have to get back to ya