OK, before we end up in the bilges, here are a few thoughts from my perspective.
There has been talk of starting another RIB magazine for years. Several people have looked into it, but so far no one has decided that it would actually be a good idea. There does seem to be a general feeling that a different magazine could be good to have though.
Traditionally, magazines exist for one reason, and one reason only: to sell advertising and make money. In a small niche with an existing dominant player, starting a new magazine is unlikely to be something that anyone would want to pitch on Dragons' Den! There may be other ways of doing things though, depending on what people want to do any why - not just the publisher, but the contributors and readers too.
Go head to head with RIB International
It might be possible to produce a magazine that is so much better than RIB International that it makes it redundant and wipes it out. If you want a profitable, proper glossy magazine, that's what you would need to do. I can't see any way that there would be sufficient advertising to support two competing magazines in this market. It would need someone really committed to go down this route.
Produce an on-line "glossy" magazine
This would avoid the printing costs of a conventional magazine, but still have similar overheads for content and layout. My experience of companies in this industry is that they are pretty conservative, and unlikely to jump at the chance to advertise in an on-line magazine. I also think it's unlikely that many people would actually pay up for a subscription in the long term.
Publish a RIB fanzine
Not bother too much with top quality production, and not really try to make a profit. Look to get enough income to cover costs but rely on volunteers. Might be an interesting read, but unlikely to gather much momentum unless it turns out to be something really special. This appears to be what Glenn is proposing, and he's obviously given it some though. My fear though is that it is likely to fade away after a few issues as the same small group of people get fed up with working their butts off for nothing. It's sort of a bit like the way things worked before the internet.
Write on-line articles
If the main reason for wanting to produce this new magazine is to share your knowledge and experience, rather than to make money, then there's already a place here - the Features
section. There's not much in it at the moment, and no one has shown any interest in submitting anything for over a year. Maybe people have missed it? Maybe I need to get out there and ask people to write things? Maybe people just don't get round to it when push comes to shove - which wouldn't bode well for the long term viability of a fanzine style mag.
What will people really buy? What will people really contribute to?