$30 annual wouldn't cut it and allow it to survive financially.
I agree in part with what you say Pinetar about the show owners, but I also know a lot of them that do look at/read Carnival Magazine every month and there are lots of shows that Dabbs sells those business card sized ads to for $1 a day per year. So I think show owners would read it, but I don't think anyone would probably be willing to pay $200 a year or even $120 a year like AB.
I'd think you could start off charging $50 a year...and see how it goes. I think advertisements from fairs, carnivals, industry suppliers, even websites like MCW could help.
As for contributors and photos, I'd think that some show owners/employees would be willing to contribute photos and so forth on a fairly regular basis. Even in the AB you don't hear "ride lists" and so forth like Carnival, but you do see where they talk to different shows at different fairs.
If the webmaster of this industry trade site had email addresses and could develop a network of owners then emailing back and forth would allow for the exchange of all kinds of information, enough that one or two people could write most of the articles.
I maintain a website for my University athletic department at www.campbellsville.edu/athletics
and I update once or twice, sometimes three times a day. I write 95% of everything on that site and it doesn't take that much time to do.
Obviously I think most MCW posters love to share photos and maybe there could be some sort of incentive rewards (such as one month free membership if you submit so many photos a month or something)
I think Pinetar is right with the password protected features. I can also envision a "showman's message board" Where people looking for people on shows could re-connect or keep up with old friends etc etc.
I could envision a classified section, that would be a mix of usedrides.com and typical classifieds with links to each advertisers website...
I think you'd have to keep it strictly professional....and leave us fans to post here at MCW along with the modelers. I think this would need to be a total "professional" industry trade site, agreeing with Pinetar.
Somebody will do this one day...it's just a matter of time. OF course AB already does but it's not just carnivals in AB. I could envision even a circus section as part of the page.
I think it could be a great resource for the industry, but getting the networking (not computerwise, but contact wise) put together would take someone already known and respected in the business. If someone like a Tom Powell were to leave AB and set this up (him at the top making contacts) or Bob Johnson of the OABA or someone like that who already has strong, established ties with virtually every show owner then I can see this thing really taking off in a hurry.