Pick a date and a location. Contact the venue and make a tentative booking. Then, only then, spread the word publicly. Right now, no one can help because no date or format is set.
Here's a tip: use cvent.com to post a RFP (request for proposal). It's a great way to contat tens of venues/hotels with only a few clicks, and never have to talk to anyone on the phone to get pricing for various locations, rooms and sizes. A geek's paradise :-)
Or you can do like I did for the Startup Conference: start small (the first conference was officially half a day but I crammed 6 hours of content, crazy). See that people loved it, and grow from there. You'll learn as you go.
I think your suggestions are really useful, but on the other hand, I think for something as broad as C, an initial test with a measuring stick is required before figuring out the specifics. I mean, with C, you could go in such diverse directions as microcontroller programming all the way to desktop application development. It may be better to figure out how to reconcile C's broad applicability before booking a venue.
Here's a tip: use cvent.com to post a RFP (request for proposal). It's a great way to contat tens of venues/hotels with only a few clicks, and never have to talk to anyone on the phone to get pricing for various locations, rooms and sizes. A geek's paradise :-)
Or you can do like I did for the Startup Conference: start small (the first conference was officially half a day but I crammed 6 hours of content, crazy). See that people loved it, and grow from there. You'll learn as you go.