Yep, the one in the above link's photo is the same as mine. It's a big'un.
After posting the above comment, I spent some more time looking around the Mr. Beer site, and found out I can order one of their 2 gallon size fermenters for "only" $10, so there's that relatively painless route I can follow.
Makes sense about the headspace and all, not wanting too much or too little.
I'm still such a noob about the whole process that I don't know things like how long beer can be stored unrefrigerated. As I recall, having refrigeration available was a major condition for the brewers of old being able to expand their routes. So of course, I assumed that if it is unpasteurized, refrigeration was necessary.
Oh, and the jargon that you guys bandy about is like a totally foreign language to me at this point. But that's okay -- I'm a linguist. And I enjoy language challenges.
Tombstone, I don't mind a bit of pedantry from time to time -- I'm often guilty of it myself. I knew that porters and stouts were not beers, but I wasn't sure that they would be categorized as ales, or if they were something different. One homebrewer I met a couple years back, who brought some of his own amazingly good porter to a party I was at, told me that brewing porters and stouts was about as hard as falling off a log, and that he had a great appreciation for the Big Guys who could so consistently brew fine lagers and pilsners. Me, I told him that I was much happier sampling his porter than having Yet Another Pale Beer.
I much prefer ales, porters, and stouts, so that will be where I'll be concentrating most of my efforts. And if this fellow is right, namely that they really are easy to brew, well then, happy days!
Incidentally, the "mix" that came with my Mr. Beer kit is Armstrong Premium Pilsner Blonde, a 1.7 kg (3.75 lb) can. It's all bulged out at the top and bottom so I'm afraid to even open it.