Someone please correct me if I am wrong here, but one big advantage to the product that IVB purchased is you can "star" the temp sensors without the need for an additional board and power supply (as opposed to the one-wire solution which requires you to "series" the sensors).
With the one wire approach wouldn't you have to purchase a data base hub type board (to get this same "star" capability), plus additional power supplys/injectors?? I would like to see an "apples to apples" comparison/pricing with ALL one-wire equipment needed to duplicate the product mentioned by the OP!
The board that IVB purchased does allow you to homerun (or star) the sensors directly. The only limitation is that you can only have one sensor for each run (as opposed to the 1-wire standards which do allow for multiple sensors on a single run - if your interface supports it). So, you are limited to four sensors but the wiring is simplified.
Other interface boards will work with multiple sensors on a single run, daisy chained, but may only have a single connection at the root. Some may have more than one connection. There are also hubs that are available (to split the daisy chain into a star pattern) as BSR mentions. In order for these to work, your interface and/or software needs to understand the hub. Again, some do and some don't.
If you want to, you can wire multiple sensors in a star pattern to a single connection (again, if the interface supports multiple sensors). However this is usually not recommended (especially for long runs) and violates the practices prescribed by Dallas Semiconductor / Maxim IC.
You can also create a star topology by using daisy-chained sensors - if you run out and back to each sensor. Run two pairs of wires from your home location to each sensor. One pair is signal and ground out to the sensor; the other is signal and ground back from the sensor. Technically, you only need the signal wire coming back, but with twisted pair it's easier/better to run both. At the sensor, you connect the signal out and signal back lines. So, your signal goes out to the sensor and then comes back along another wire. Then, you connect the "back signal" to the outgoing signal for the next sensor. You are creating much longer runs, but electrically it remains a daisy-chain instead of a star. I don't do this with my 1-wire stuff, but I do do it for my RS-485 network.
I've ignored the third wire for power here - assuming that you will be running parasitically. If you want to run power to each sensor (and some 1-wire sensors will require it), that will add another wire - but you don't have to return that to the home location if you are creating the star/daisy-chain configuration described above.