I'm happy to join in - a quarterly basis doesn't sound like too much of a stretch.
I quite like writing articles, and I'm happy to comment on things from a developer's perspective such as upcoming features (From the Orbiter beta versions, extensions to the API and so on) as well as my personal projects and those of anyone who cares to talk to me about them (on the understanding that I'd then devote a portion of an article to it).
In addition I'm thinking I can include bits about new forum features or changes therein, and perhaps give a staff slant on things (I'd have to talk with the other staff first and make sure on that part).
However, as Pablo notes, I think you might be jumping ahead a little quickly. I can understand the desire to get something made and done quickly, but this isn't how lasting things remain around - just look at my "Radio station" for proof of that. Better would be to see how much content you actually have before deciding on the number of pages - of course, we don't want to wind up having a 90-page PDF to compile and distribute, but I don't think that'll happen, at least not in the early stages.
"Real World" magazines have very few defined pages until they know what will be going in them. They might have a particular arrangement of opening pages, such as a recurring "Editor's letter" and a table of contents / foreword on what you'll find in this issue, but it's rare that they'll define how many pages an individual issue will have before they know how many pages they can actually fill.
It's better to have five pages of real content than ten pages where five are clearly filler.
---------- Post added at 14:57 ---------- Previous post was at 14:56 ----------
Heh, I remember starting off coding an MFD. It's not the most clearly-documented portion of Orbiter development...