@max: "maybe I can find one somewhere on our path..."
Are you planning on driving a moderate-size truck (with liftgate, as these are quite heavy) to Dayton? I had a friend many years ago who had a miniaturized version of this he used for his model railroad hobby. Now that he's retired, he has a basement workshop that puts mine to shame: it's a fully-equipped wood AND metal-working shop with pro-quality and size machine tools.
@mhrackin: Harbor Freight has an interesting (and very inexpensive) variation...
Jason from Instrument Meter Specialities (see my The Moon is a Harsh Mistress blog) told me about something called a Shopsmith Mark V (now they do a Mark 7) -- I looked them up and it does seem to be a very useful multipurpose tool -- you can pick them up relatively cheap on eBay, but they are really heavy so you typically have to pick thm up yourself ... maybe I can find one somewhere on our path on our forthcoming Road Trip to Hamvention
Harbor Freight has an interesting (and very inexpensive) variation. It has TWO cutting bars which would help keep it centered and perpendicular (but would have to be maually set to precisely the same radius!). Go to their web site and search for "Carbide Tip Adjustable Circle Cutter "
That circle-cutting tool is called a "circle cutter" in the trade. I've had one for years, but unless you have a very good drill press, you can't cut an accurate and neat large (meter-sized??) hole with one. They really suck in a hand drill. Hole saws work much better unless you need to cut a smooth round hole through a very thick material. They do make extra-deep hole saws for that, but they are hard to find and rather expensive.
Those big round saws that are at the top of page 3 - I've ised the cut out from those as little wheels.
There's another tool with the same purpose. It's got a standard drill in the center and a bar that goes off perpendicular. That bar has a cutting blade that slides to adjust so you can make big holes of just about any size with it.
This reminds me of Steve Ciarcia who ran the Circuit Cellar magazine. He used to (& probably still does) erase the contents of old hard drives by putting them on a stump & using them for target practice!